Vol. 117 No. 5 May 2014
Clinicopathologic analysis and syndecan-1 and Ki-67 expression in calcifying cystic odontogenic tumors, dentinogenic ghost cell tumor, and ghost cell odontogenic carcinoma Wagner Gomes da Silva, DDS,a Teresa Cristina Ribeiro Bartholomeu dos Santos, DDS, MSc,b Márcia Grillo Cabral, DDS, PhD,c Rebeca Souza Azevedo, DDS, PhD,d and Fábio Ramôa Pires, DDS, PhDe State University of Rio de Janeiro, Estácio de Sá University, and Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil; Fluminense Federal University, Nova Friburgo, Rio de Janeiro, Brazil
Objective. Benign and malignant tumor cells can express altered adhesion properties, and these features can be associated with their proliferative and invasive characteristics. This study aimed to evaluate syndecan-1 and Ki-67 expression in ghost cellecontaining odontogenic tumors. Study Design. Clinical data were retrieved from laboratory records, and hematoxylin-eosin-stained slides and sections, labeled with monoclonal antibodies anti-syndecan-1 and anti-Ki-67 using the immunoperoxidase technique, were evaluated. Results. Included were 21 central calcifying cystic odontogenic tumors (CCOTs) (4 associated with odontoma), 2 peripheral CCOTs, 1 dentinogenic ghost cell tumor, and 1 ghost cell odontogenic carcinoma (GCOC). Syndecan-1 was mainly expressed in cells resembling stellate reticulum and in stromal cells from the fibrous capsule. The mean Ki-67 labeling index was 4.1% (49.3% for GCOC), but it was not associated with syndecan-1 expression. Conclusions. Syndecan-1 is variably expressed in cells resembling the stellate reticulum, stromal cells, and basal cells and might be associated with the biology of these tumors. (Oral Surg Oral Med Oral Pathol Oral Radiol 2014;117:626-633)
The calcifying odontogenic cyst was first described by Gorlin et al.1 in 1962 and was reclassified as an odontogenic tumor (OT) in the World Health Organization (WHO) second classification of odontogenic cysts and tumors in 1992.2 Owing to the identification of both cystic and solid subtypes, this tumor was reclassified to form 2 distinct entities, which included the calcifying cystic odontogenic tumor (CCOT) (a benign cystic variant) and the dentinogenic ghost cell tumor (DGCT) (a benign solid variant), in the most recent WHO classification.3 Additionally, there is a malignant OT composed of several histologic components similar to the ones found in the CCOT and DGCT, named ghost cell odontogenic carcinoma (GCOC), completing the triad of classic ghost celle The authors thank the FAPERJ (Foundation for Research Support of the State of Rio de Janeiro) and CNPq (National Council for Scientific and Technological Development) for financial support for this study. The partial results of the present study were presented as a poster during the 16th International Congress on Oral Pathology and Medicine and the 20th Brazilian Congress on Oral Medicine and Pathology in São Pedro, São Paulo, Brazil, July 30 to August 3, 2012. An abstract of this study was published in October 2012 (Oral Surg Oral Med Oral Pathol Oral Radiol 2012;114:e136). a Oral Pathology, State University of Rio de Janeiro. b Professor, Oral Pathology, State University of Rio de Janeiro; Oral Pathology, Estácio de Sá University. c Professor, Oral Pathology, Federal University of Rio de Janeiro. d Professor, Oral Pathology, Fluminense Federal University. e Professor, Oral Pathology, State University of Rio de Janeiro. Received for publication Jun 3, 2013; returned for revision Jan 9, 2014; accepted for publication Jan 14, 2014. Ó 2014 Elsevier Inc. All rights reserved. 2212-4403/$ - see front matter http://dx.doi.org/10.1016/j.oooo.2014.01.021
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containing OTs.3,4 Diagnostic criteria for CCOTs, DGCTs, and GCOCs have been established, but these tumors represent a heterogeneous group, showing a wide spectrum of clinical and radiologic presentations, solid and cystic growth patterns, histologic diversity and superimposition, and variable biologic behavior.5,6 Syndecan-1 is a transmembrane heparan sulfate proteoglycan present in different cell types and associated with cytoskeletal organization, growth factor signaling, cell-cell adhesion, extracellular matrix adhesion, and epithelial-mesenchymal interactions.7-9 Some studies have found that syndecan-1 can be an important proteoglycan associated with the process of invasion in several neoplasms, including odontogenic tumors.7,8 There are no previously reported studies focusing on syndecan-1 expression in CCOTs, DGCTs, and GCOCs; thus, the aim of the present study was to compare the histologic pattern and syndecan-1 and Ki-67 immunoexpression in a series of ghost cellecontaining OTs.
Statement of Clinical Relevance Syndecan-1 expression has been associated with tumor invasion in some benign and malignant neoplasms. Ghost cellecontaining odontogenic tumors include different entities with variable histologic pattern and biologic behavior, and there are no studies focusing on syndecan-1 expression in these tumors.
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MATERIAL AND METHODS CCOT, DGCT, and GCOC specimens were retrieved from the files of 3 oral pathology services in Rio de Janeiro, Rio de Janeiro, Brazil (State University of Rio de Janeiro, Federal University of Rio de Janeiro, and Estácio de Sá University). Sections from all cases, 5 mm thick and stained with hematoxylin-eosin, were carefully reviewed under light microscopy, and those presenting the typical features of CCOTs, DGCTs, and GCOCs according to the criteria described by Barnes et al.3 were selected. Cases with no demographic, clinical, and radiologic information and without representative tissue specimens on the paraffin blocks were excluded from the study. Clinical and radiologic information from all tumors was retrieved from the laboratory records. Immunohistochemical analysis was performed on 3-mm tissue sections mounted on silanized slides and treated with citrate buffer (pH, 6.0) in the microwave for antigen retrieval. Inhibition of endogenous peroxidase activity was performed using 10% hydrogen peroxide, followed by an overnight incubation of the sections with primary monoclonal antibodies antie human syndecan-1 (CD138, MI15 clone; Dako Corporation, Carpinteria, CA, USA; dilution 1:200) and anti-Ki-67 (MIB-1 clone; Dako Corporation; dilution 1:200). Next, sections were incubated with biotinylated secondary antibodies and the streptavidin/ biotin system conjugated to peroxidase (LSAB þ Biotin-Labeled streptavidin; Dako Corporation). The reaction product was visualized with the aid of diaminobenzidine (Dako Corporation) and counterstained with Mayer hematoxylin. Negative controls (absence of the primary antibodies) and positive controls (normal oral epithelium for syndecan-1 and squamous cell carcinoma for Ki-67) were used in all reactions. Expression of syndecan-1 was descriptively analyzed in each histologic component of the tumors. The entire section immunostained for syndecan-1 was analyzed, and representative areas containing the cellular types characteristic of each tumor type (CCOT, DGCT, and GCOC) were evaluated. Cells containing positive membranous immunostaining were considered positive for syndecan-1 expression. The Ki-67 labeling index (expressed as a percentage) was established for each case as the mean number of positive cells in 100 cells analyzed using 10 different high-power fields (at 40 magnification) under light microscopy. Data obtained from the laboratory charts, from analysis of the hematoxylin-eosin-stained slides, and from immunohistochemical reactions were analyzed with the aid of SPSS, version 17.0 (SPSS Inc, Chicago, IL, USA), considering 5% as the significance level (P < .05). The Fisher exact test was used to compare the
ORIGINAL ARTICLE Gomes da Silva et al. 627
differences of syndecan-1 expression in the histologic components of each tumor group; the t test was used to compare the mean Ki-67 labeling indexes. The current study was a retrospective study; no patients were interviewed or examined. All information was retrieved from laboratory records and from histologic analysis of the slides. We followed the Helsinki Declaration for the study of human participants.
RESULTS The study consisted of 17 (68%) central CCOTs, 4 (16%) central CCOTs associated with odontoma (CCOTos), 2 (8%) peripheral CCOTs (CCOTps), 1 (4%) central DGCT, and 1 (4%) central GCOC. Apart from the 4 CCOTos, 1 central CCOT was associated with an ameloblastic fibroma in the posterior mandible of a 17-year-old girl. The mean age of the patients was 27.1 years (standard deviation [SD], 18.1; range, 969 years). The maxilla was slightly more affected than the mandible, and radiolucencies with radiopaque foci presented in 52% of the available images. The detailed distribution of the clinical and radiologic parameters from the 25 studied tumors is included in Table I. The mean radiologic diameter of the tumors was 43.8 mm (SD, 22.8; range, 15-80 mm), and the time of complaint reported by the patients showed a mean of 36.6 months (SD, 56.5; range, 1-180 months). Histologic analysis of the tumors found that, apart from the typical morphologic features related to each subtype, ghost cells and calcifications were prominent in 44% and 32% of the cases, respectively. Focal ameloblastomatous proliferations and islands of odontogenic remnants in the fibrous capsule were observed in 60% and 68% of the cases, respectively. Ameloblastomatous proliferation was a prominent feature in CCOTps, the DGCT, and the GCOC, but it was not observed in CCOTos. Dentinoid material was a prominent feature in 9 tumors (36%). The GCOC showed tumor cells with enlarged nuclei and decreased nuclearcytoplasm ratio, prominent nucleoli, foci of necrosis, and hemorrhage in selected areas. Table II summarizes the distribution of histologic features observed in each specific entity, and Figure 1 shows representative histologic features from select tumors. Considering the histologic components found in all tumors, basal cells (defined as the cells located in the first epithelial layer, in direct contact with basal lamina/ connective tissue) and cells resembling the stellate reticulum expressed syndecan-1 in 36% and 72% of the cases, respectively (Figure 2, A). The staining patterns seen in ghost cells and calcifications were not considered positive, because they were not membranous like the pattern visualized in other cell types (see
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Table I. Clinical and radiologic data according to final diagnosis
Parameter
Calcifying cystic Calcifying cystic Calcifying cystic odontogenic tumor þ odontogenic tumor, Dentinogenic Ghost cell odontogenic tumor odontoma peripheral ghost cell tumor odontogenic carcinoma Total
Age (y) Up to 20 >21 Not available Gender Male Female Location Maxilla Mandible Radiologic image Radiolucency Radiolucency/radiopacity Not available Impacted tooth Absent Present
8 9 d
1 2 1
d 2 d
1 d d
d 1 d
10 14 1
8 9
3 1
1 1
1 d
1 d
14 11
10 7
3 1
d 2
d 1
1 d
14 11
8 7 2
d 4 d
1 d d
1 d d
10 11 2
9 8
2 2
d 1
1 d
14 11
Not applicable Not applicable Not applicable 2 d
Table II. Histologic features according to final diagnosis
Histologic features Ghost cells Focal Prominent Ameloblastomatous proliferation Absent Present Calcification Not prominent Prominent Epithelial odontogenic remnants in the fibrous capsule Absent Present Dentinoid material Absent/Not prominent Prominent
Calcifying cystic Calcifying cystic Calcifying cystic Dentinogenic Ghost cell odontogenic odontogenic odontogenic ghost odontogenic tumor tumor þ odontoma tumor, peripheral cell tumor carcinoma Total 11 6
2 2
d 2
1 d
d 1
14 11
6 11
4 d
d 2
d 1
d 1
10 15
11 6
3 1
1 1
1 d
1 d
17 8
3 14
3 1
1 1
1 d
d 1
8 17
12 5
3 1
d 2
1 d
d 1
16 9
Figure 2, B). Syndecan-1 expression in epithelial odontogenic remnants in the capsule and ameloblastomatous proliferations was evaluated only in the cases presenting these features and revealed immunopositivity in 10 of 17 cases (59%) and in 9 of 15 cases (60%), respectively (see Figure 2, C, D). Analysis of the fibrous capsule found that syndecan-1-positive stromal spindle cells were found in 68% of the cases (see Figure 2, E). Additionally, syndecan-1-labeled plasma cells were present in the connective tissue of the capsule in 7 cases (28%). A strong labeling pattern of syndecan-1 expression was observed in superficial stromal spindle cells of the capsule in several regions of all tumor groups, except for the GCOC (see Figure 2, F). Syndecan-1 expression was observed in basal cells
that were located in 35% of the CCOTs, 100% of the CCOTps and the GCOC, and 0% of the CCOTos and the DGCT (P ¼ .086). Syndecan-1 was frequently expressed in the cells resembling the stellate reticulum and ameloblastomatous proliferation in the majority of the tumor groups (CCOT, DGCT, and GCOC) (Table III). The Ki-67 labeling index showed a mean of 4.1% (range, 0%-49.3%) per high-power field (Figure 3, A, B). The Ki-67 labeling index for each specific histologic subtype was 2.2% for CCOTs, 7.1% for CCOTps, and 49.3% for the GCOC. There were no Ki-67-labeled cells in the CCOTos or the DGCT. The mean Ki-67 labeling index was higher in cases that displayed ameloblastomatous proliferations (6.5 vs 0.17 in cases
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ORIGINAL ARTICLE Gomes da Silva et al. 629
Fig. 1. A, Typical histologic features of a calcifying cystic odontogenic tumor showing the epithelial lining that contains basal cells, cells resembling the stellate reticulum, and ghost cells (hematoxylin-eosin, original magnification 40). B, Calcifying cystic odontogenic tumor showing ghost cells, a cystic area, and an ameloblastomatous proliferation on the fibrous capsule (hematoxylineosin, original magnification 10). C, Detail of an area predominantly composed of ghost cells and calcification foci (hematoxylineosin, original magnification 10). D, Ghost cell odontogenic carcinoma showing hyperchromatic epithelial cells, abundant ghost cells, and hemorrhage (hematoxylin-eosin, original magnification 10).
with no proliferations; P ¼ .142) and prominent ghost cells (7.5 vs 1.27 in cases with focal ghost cells; P ¼ .136), but the differences were not statistically significant. The majority of cases, except for the GCOC, presented very low proliferative indexes; therefore, it was not possible to correlate these values with any of the studied parameters. Figure 4 shows a comparison of histologic features and syndecan-1 and Ki-67 expression levels in CCOT and GCOC.
DISCUSSION CCOTs, DGCTs, and GCOCs are well-characterized entities, and the clinical and radiologic features of the tumors included in the present study reinforce previously reported data.4-6,10-16 However, apart from their specific microscopic diagnostic criteria, they can share common histologic characteristics, including cells resembling the stellate reticulum of the enamel organ, basal polarized columnar to cuboidal cells, and ghost cells, as also exemplified by the present results. In epithelial tissue, syndecan-1 has been associated with binding to proteins of the extracellular matrix, mediating epithelial-stromal interactions and cell proliferation.7 Some studies have found controversial results regarding the role of syndecan-1 expression and the biologic behavior of select tumors, including their invasive capacity.7 Downregulation of syndecan-1 in
epithelial tumor cells and the alteration of its expression from epithelial tumor cells to stromal cells and extracellular matrix have been implicated in tumor invasiveness.7 Loss of syndecan-1 expression by epithelial cells has been associated with a poor prognosis in endometrial, lung, gastric, colorectal, and oral cancers, and increased syndecan-1 expression in tumor cells can be associated with a poor prognosis in breast carcinomas.8,17,18 Increased stromal expression of syndecan-1 has been associated with a poor prognosis in endometrial, gastric, ovarian, breast, and oral cancers.17,18 The mechanisms involved in these processes remain unknown, but it has been suggested that syndecan-1 expression by fibroblasts creates a favorable environment for tumor growth because this molecule binds to several epithelial mitogens, including hepatocyte and epidermal growth factors.19 Syndecan-1 expression in odontogenic cysts and OTs has been previously reported, and results have suggested a possible prognostic significance of this molecule in these entities. Decreased expression of syndecan-1 was observed in solid ameloblastomas compared with unicystic ameloblastomas; additionally, recurrent ameloblastomas showed decreased syndecan1 expression compared with nonrecurrent ameloblastomas, suggesting that decreased syndecan-1 expression may be associated with increased
ORAL AND MAXILLOFACIAL PATHOLOGY 630 Gomes da Silva et al.
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Fig. 2. A, Prominent syndecan-1 expression in cells resembling the stellate reticulum and focal syndecan-1 expression in basal cells in a calcifying cystic odontogenic tumor (immunoperoxidase, 40). B, Cytoplasmic syndecan-1 expression in ghost cells in a calcifying cystic odontogenic tumor (arrow, upper left corner) (immunoperoxidase, 40). C, Syndecan-1 expression in odontogenic epithelial remnants in a calcifying cystic odontogenic tumor (immunoperoxidase, 40). D, Syndecan-1 expression in ameloblastomatous proliferations on the capsule in a calcifying cystic odontogenic tumor (immunoperoxidase, 40). E, Syndecan-1 expression in the epithelial component and superficial stromal cells in a calcifying cystic odontogenic tumor (immunoperoxidase, 10). F, Absence of syndecan-1 expression in stromal cells in a ghost cell odontogenic carcinoma (immunoperoxidase, 10).
aggressiveness of these tumors.8,20 Expression of syndecan-1 has also been found to be decreased in ameloblastic carcinomas compared with peripheral ameloblastomas and desmoplastic ameloblastomas.21 Additionally, decreased expression of syndecan-1 has been found in ameloblastomas compared with keratocystic odontogenic tumors and dentigerous cysts.20 Syndecan-1 has been found to be expressed in ameloblasts, cuboidal cells, and squamous areas in ameloblastomas; in the stromal component, it has been found to be weak in stromal spindle cells but strong in the extracellular matrix and basal membrane, supporting that this molecule can be associated with their invasiveness.7 Syndecan-1 was identified in odontogenic
epithelium and granular cells in central granular cell OTs, suggesting an important role in cell-cell adhesion and reciprocal interaction between these cells.22 High syndecan-1 expression was observed in the epithelial lining of radicular and dentigerous cysts and keratocystic odontogenic tumors.9 Nevertheless, expression of syndecan-1 has not been previously studied in CCOTs, DGCTs, and GCOCs. As shown in Table III, syndecan-1 expression was identified in almost all cellular components from the 5 studied groups. Cells resembling the stellate reticulum, ameloblastomatous proliferations, and odontogenic epithelial remnants expressed syndecan-1 more frequently than basal cells. Although there were some
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ORIGINAL ARTICLE Gomes da Silva et al. 631
Table III. Distribution of syndecan-1 expression in each histologic component according to final diagnosis
Histologic component Basal cells Cells resembling stellate reticulum Spindle cells in the capsule Odontogenic epithelial remnants Ameloblastomatous proliferation
Calcifying cystic Calcifying cystic Ghost cell Calcifying cystic odontogenic tumor þ odontogenic tumor, Dentinogenic odontogenic odontogenic tumor odontoma peripheral ghost cell tumor carcinoma
Total
P
6/17 (35%) 11/17 (65%)
0/4 (0%) 3/4 (75%)
2/2 (100%) 2/2 (100%)
0/1 (0%) 1/1 (100%)
1/1 (100%) 9/25 (36%) .086 1/1 (100%) 18/25 (72%) .732
13/17 (77%) 9/14 (64%)
1/4 (25%) 1/1 (100%)
2/2 (100%) 0/1 (0%)
1/1 (100%) 0/0 (0%)
0/1 (0%) 0/1 (0%)
6/11 (55%)
0/0 (0%)
1/2 (50%)
1/1 (100%)
1/1 (100%)
17/25 (68%) .112 10/17 (59%) .292 9/15 (60%) .670
Fig. 3. Ki-67 expression in calcifying cystic odontogenic tumor (A, immunoperoxidase, 40; B, immunoperoxidase, 100).
Fig. 4. A-C, Calcifying cystic odontogenic tumor. A, Typical histologic features (hematoxylin-eosin, original magnification 40). B, Syndecan-1 expression mostly in cells that resemble stellate reticulum and stromal cells (immunoperoxidase, 40). C, Focal Ki-67 expression (immunoperoxidase, 40). D-F, Ghost cell odontogenic carcinoma. D, Characteristic histologic features (hematoxylin-eosin, original magnification 40). E, Syndecan-1 expression in hyperchromatic tumor cells (immunoperoxidase, 40). F, Ki-67 expression in approximately half of the tumor cells (immunoperoxidase, 40).
differences in the number of tumors expressing syndecan-1 in each histologic component, statistically significant differences were not encountered. Basal cells expressed syndecan-1 in approximately one-third of the
cases, contrary to what has been previously reported for odontogenic cystic lesions.9 In contrast, in some areas, a strong labeling pattern of syndecan-1 expression was observed in superficial stromal cells of the capsule,
ORAL AND MAXILLOFACIAL PATHOLOGY 632 Gomes da Silva et al.
possibly representing undifferentiated mesenchymal cells, fibroblasts, or myofibroblasts. Although the present study included only 1 GCOC, no evidence of stromal syndecan-1 expression was observed in this specific case. In previous reports, syndecan-1 expression in ameloblastomas was higher in cells resembling the stellate reticulum than in ameloblasts.20 Similarly, our results showed higher syndecan-1 expression in cells resembling the stellate reticulum in CCOTs, DGCTs, and GCOCs. In the current study, the majority of cases showing odontogenic epithelial remnants and ameloblastomatous proliferation on the capsule also showed an intense syndecan-1 staining in the proliferative areas, unlike the expression in basal cells; the significance of this expression pattern has not been elucidated. It seems that both decreased epithelial syndecan-1 expression and increased stromal syndecan-1 expression are common features in CCOTs, DGCTs, and GCOCs. The Ki-67 labeling index has been frequently used to estimate the cellular proliferative capacity in both benign and malignant tumors, including OTs and, more specifically, ghost cellecontaining OTs.6,16 In previous reports, the Ki-67 labeling index was very low or even absent, except for select DGCTs and all GCOCs.6,16 As expected, in the current study, the Ki-67 labeling index was prominent in the GCOC and, surprisingly, it was also relatively high in CCOTps, but it was not observed in the DGCT. Both CCOTps included in the present study presented a prominent inflammatory infiltrate, and this would have influenced the proliferative indexes found in these tumors. Additionally, cases presenting ameloblastomatous proliferation showed a higher mean Ki-67 labeling index, although the difference was not statistically significant compared with cases without this histologic feature.
CONCLUSION Syndecan-1 was mostly expressed in cells resembling stellate reticulum and stromal cells from the fibrous capsule, especially in the DGCT and the CCOTs; in contrast, syndecan-1 expression in basal cells was found in approximately one-third of the cases. Therefore, our results show that syndecan-1 expression is variable in cells resembling the stellate reticulum, stromal cells, and basal cells in ghost cellecontaining OTs. Given that it is accepted that the behavior of CCOTs, DGCTs, and GCOCs is distinct, the differential expression of proteoglycans associated with cell adhesion and growth factor signaling could at least partially be associated with these characteristics. REFERENCES 1. Gorlin RJ, Pindborg JJ, Clausen FP, Vickers RA. The calcifying odontogenic cystda possible analogue of the cutaneous
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calcifying epithelioma of Malherbe: an analysis of fifteen cases. Oral Surg Oral Med Oral Pathol. 1962;15:1235-1243. Kramer IRH, Pindborg JJ, Shear M. Histological typing of odontogenic tumours. In:World Health Organization International Histological Classification of Tumours. 2nd ed. Berlin, Germany: Springer-Verlag; 1992. Barnes L, Eveson JW, Reichart P, Sidransky D, eds. Odontogenic tumours. In: World Health Organization Classification of Tumours: Pathology and Genetics of Head and Neck Tumours. Lyon, France: IARC Press; 2005:283-327. Ledesma-Montes C, Gorlin RJ, Shear M, et al. International collaborative study on ghost cell odontogenic tumours: calcifying cystic odontogenic tumour, dentinogenic ghost cell tumour and ghost cell odontogenic carcinoma. J Oral Pathol Med. 2008;37: 302-308. Li TJ, Yu SF. Clinicopathologic spectrum of the so-called calcifying odontogenic cysts: a study of 21 intraosseous cases with reconsideration of the terminology and classification. Am J Surg Pathol. 2003;27:372-384. Fregnani ER, Pires FR, Quezada RD, Shih IM, Vargas PA, de Almeida OP. Calcifying odontogenic cyst: clinicopathological features and immunohistochemical profile of 10 cases. J Oral Pathol Med. 2003;32:163-170. Leocata P, Villari D, Fazzari C, Lentini M, Fortunato C, Nicòtina PA. Syndecan-1 and Wingless-type protein-1 in human ameloblastomas. J Oral Pathol Med. 2007;36:394-399. Bologna-Molina R, Mosqueda-Taylor A, Lopez-Corella E, et al. Syndecan-1 (CD138) and Ki-67 expression in different subtypes of ameloblastomas. Oral Oncol. 2008;44:805-811. Nadalin MR, Fregnani ED, Silva-Sousa YTC, Perez DEC. Syndecan-1 (CD138) and Ki-67 expression in odontogenic cystic lesions. Braz Dent J. 2011;22:223-229. Buchner A. The central (intraosseous) calcifying odontogenic cysts: an analysis of 215 cases. J Oral Maxillofac Surg. 1991;49: 330-339. Hong SP, Ellis GL, Hartman KS. Calcifying odontogenic cyst: a review of 92 cases with re-evaluation of their nature as cysts or neoplasms, the nature of ghost cells, and subclassification. Oral Surg Oral Med Oral Pathol. 1991;72:56-64. Sun G, Huang X, Hu Q, Yang X, Tang E. The diagnosis and treatment of dentinogenic ghost cell tumor. Int J Oral Maxillofac Surg. 2009;38:1179-1183. Sun ZJ, Zhao YF, Zhang L, Li ZB, Chen XM, Zhang WF. Odontogenic ghost cell carcinoma in the maxilla: a case report and literature review. J Oral Maxillofac Surg. 2007;65: 1820-1824. Buchner A, Merrell PW, Hansen LS, Leider AS. Peripheral (extraosseous) calcifying odontogenic cyst: a review of forty-five cases. Oral Surg Oral Med Oral Pathol. 1991;72:65-70. Toida M. So-called calcifying odontogenic cyst: review and discussion on the terminology and classification. J Oral Pathol Med. 1998;27:49-52. Yoshida M, Kumamoto H, Ooya K, Mayanagi H. Histopathological and immunohistochemical analysis of calcifying odontogenic cysts. J Oral Pathol Med. 2001;30:582-588. Hasengaowa, Kodama J, Kusumoto T, Shinyo Y, Seki N, Hiramatsu Y. Prognostic significance of syndecan-1 expression in human endometrial cancer. Ann Oncol. 2005;16: 1109-1115. Mukunyadzi P, Liu K, Hanna EY, Suen JY, Fan CY. Induced expression of syndecan-1 in the stroma of head and neck squamous cell carcinoma. Mod Pathol. 2003;16:796-801. Maeda T, Alexander CM, Friedl A. Induction of syndecan-1 expression in stromal fibroblasts promotes proliferation of human breast cancer cell. Cancer Res. 2004;64:612-621.
OOOO Volume 117, Number 5 20. Al-Otaibi O, Khounganian R, Anil S, Rajendran R. Syndecan-1 (CD138) surface expression marks cell type and differentiation in ameloblastoma, keratocystic odontogenic tumor and dentigerous cyst. J Oral Pathol Med. 2013;42:186-193. 21. Bologna-Molina R, Mosqueda-Taylor A, Lopez-Corella E, et al. Comparative expression of syndecan-1 and Ki-67 in peripheral and desmoplastic ameloblastomas and ameloblastic carcinoma. Pathol Int. 2009;59:229-233. 22. Mesquita AT, Santos CR, Gomez RS, Jorge J, Léon JE, de Almeida OP. Central granular cell odontogenic tumor: a histopathologic and immunohistochemical study. Ann Diagn Pathol. 2009;13:405-412.
ORIGINAL ARTICLE Gomes da Silva et al. 633 Reprint requests: Fábio Ramôa Pires, DDS, PhD Department of Oral Pathology School of Dentistry State University of Rio de Janeiro Boulevard 28 de Setembro, 157 Vila Isabel 20551-030 Rio de Janeiro, RJ Brazil [email protected]
Clinicopathologic analysis and syndecan-1 and Ki-67 expression in calcifying cystic odontogenic tumors, dentinogenic ghost cell tumor, and ghost cell odontogenic carcinoma Wagner Gomes da Silva, DDS,a Teresa Cristina Ribeiro Bartholomeu dos Santos, DDS, MSc,b Márcia Grillo Cabral, DDS, PhD,c Rebeca Souza Azevedo, DDS, PhD,d and Fábio Ramôa Pires, DDS, PhDe State University of Rio de Janeiro, Estácio de Sá University, and Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil; Fluminense Federal University, Nova Friburgo, Rio de Janeiro, Brazil
Objective. Benign and malignant tumor cells can express altered adhesion properties, and these features can be associated with their proliferative and invasive characteristics. This study aimed to evaluate syndecan-1 and Ki-67 expression in ghost cellecontaining odontogenic tumors. Study Design. Clinical data were retrieved from laboratory records, and hematoxylin-eosin-stained slides and sections, labeled with monoclonal antibodies anti-syndecan-1 and anti-Ki-67 using the immunoperoxidase technique, were evaluated. Results. Included were 21 central calcifying cystic odontogenic tumors (CCOTs) (4 associated with odontoma), 2 peripheral CCOTs, 1 dentinogenic ghost cell tumor, and 1 ghost cell odontogenic carcinoma (GCOC). Syndecan-1 was mainly expressed in cells resembling stellate reticulum and in stromal cells from the fibrous capsule. The mean Ki-67 labeling index was 4.1% (49.3% for GCOC), but it was not associated with syndecan-1 expression. Conclusions. Syndecan-1 is variably expressed in cells resembling the stellate reticulum, stromal cells, and basal cells and might be associated with the biology of these tumors. (Oral Surg Oral Med Oral Pathol Oral Radiol 2014;117:626-633)
The calcifying odontogenic cyst was first described by Gorlin et al.1 in 1962 and was reclassified as an odontogenic tumor (OT) in the World Health Organization (WHO) second classification of odontogenic cysts and tumors in 1992.2 Owing to the identification of both cystic and solid subtypes, this tumor was reclassified to form 2 distinct entities, which included the calcifying cystic odontogenic tumor (CCOT) (a benign cystic variant) and the dentinogenic ghost cell tumor (DGCT) (a benign solid variant), in the most recent WHO classification.3 Additionally, there is a malignant OT composed of several histologic components similar to the ones found in the CCOT and DGCT, named ghost cell odontogenic carcinoma (GCOC), completing the triad of classic ghost celle The authors thank the FAPERJ (Foundation for Research Support of the State of Rio de Janeiro) and CNPq (National Council for Scientific and Technological Development) for financial support for this study. The partial results of the present study were presented as a poster during the 16th International Congress on Oral Pathology and Medicine and the 20th Brazilian Congress on Oral Medicine and Pathology in São Pedro, São Paulo, Brazil, July 30 to August 3, 2012. An abstract of this study was published in October 2012 (Oral Surg Oral Med Oral Pathol Oral Radiol 2012;114:e136). a Oral Pathology, State University of Rio de Janeiro. b Professor, Oral Pathology, State University of Rio de Janeiro; Oral Pathology, Estácio de Sá University. c Professor, Oral Pathology, Federal University of Rio de Janeiro. d Professor, Oral Pathology, Fluminense Federal University. e Professor, Oral Pathology, State University of Rio de Janeiro. Received for publication Jun 3, 2013; returned for revision Jan 9, 2014; accepted for publication Jan 14, 2014. Ó 2014 Elsevier Inc. All rights reserved. 2212-4403/$ - see front matter http://dx.doi.org/10.1016/j.oooo.2014.01.021
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containing OTs.3,4 Diagnostic criteria for CCOTs, DGCTs, and GCOCs have been established, but these tumors represent a heterogeneous group, showing a wide spectrum of clinical and radiologic presentations, solid and cystic growth patterns, histologic diversity and superimposition, and variable biologic behavior.5,6 Syndecan-1 is a transmembrane heparan sulfate proteoglycan present in different cell types and associated with cytoskeletal organization, growth factor signaling, cell-cell adhesion, extracellular matrix adhesion, and epithelial-mesenchymal interactions.7-9 Some studies have found that syndecan-1 can be an important proteoglycan associated with the process of invasion in several neoplasms, including odontogenic tumors.7,8 There are no previously reported studies focusing on syndecan-1 expression in CCOTs, DGCTs, and GCOCs; thus, the aim of the present study was to compare the histologic pattern and syndecan-1 and Ki-67 immunoexpression in a series of ghost cellecontaining OTs.
Statement of Clinical Relevance Syndecan-1 expression has been associated with tumor invasion in some benign and malignant neoplasms. Ghost cellecontaining odontogenic tumors include different entities with variable histologic pattern and biologic behavior, and there are no studies focusing on syndecan-1 expression in these tumors.
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MATERIAL AND METHODS CCOT, DGCT, and GCOC specimens were retrieved from the files of 3 oral pathology services in Rio de Janeiro, Rio de Janeiro, Brazil (State University of Rio de Janeiro, Federal University of Rio de Janeiro, and Estácio de Sá University). Sections from all cases, 5 mm thick and stained with hematoxylin-eosin, were carefully reviewed under light microscopy, and those presenting the typical features of CCOTs, DGCTs, and GCOCs according to the criteria described by Barnes et al.3 were selected. Cases with no demographic, clinical, and radiologic information and without representative tissue specimens on the paraffin blocks were excluded from the study. Clinical and radiologic information from all tumors was retrieved from the laboratory records. Immunohistochemical analysis was performed on 3-mm tissue sections mounted on silanized slides and treated with citrate buffer (pH, 6.0) in the microwave for antigen retrieval. Inhibition of endogenous peroxidase activity was performed using 10% hydrogen peroxide, followed by an overnight incubation of the sections with primary monoclonal antibodies antie human syndecan-1 (CD138, MI15 clone; Dako Corporation, Carpinteria, CA, USA; dilution 1:200) and anti-Ki-67 (MIB-1 clone; Dako Corporation; dilution 1:200). Next, sections were incubated with biotinylated secondary antibodies and the streptavidin/ biotin system conjugated to peroxidase (LSAB þ Biotin-Labeled streptavidin; Dako Corporation). The reaction product was visualized with the aid of diaminobenzidine (Dako Corporation) and counterstained with Mayer hematoxylin. Negative controls (absence of the primary antibodies) and positive controls (normal oral epithelium for syndecan-1 and squamous cell carcinoma for Ki-67) were used in all reactions. Expression of syndecan-1 was descriptively analyzed in each histologic component of the tumors. The entire section immunostained for syndecan-1 was analyzed, and representative areas containing the cellular types characteristic of each tumor type (CCOT, DGCT, and GCOC) were evaluated. Cells containing positive membranous immunostaining were considered positive for syndecan-1 expression. The Ki-67 labeling index (expressed as a percentage) was established for each case as the mean number of positive cells in 100 cells analyzed using 10 different high-power fields (at 40 magnification) under light microscopy. Data obtained from the laboratory charts, from analysis of the hematoxylin-eosin-stained slides, and from immunohistochemical reactions were analyzed with the aid of SPSS, version 17.0 (SPSS Inc, Chicago, IL, USA), considering 5% as the significance level (P < .05). The Fisher exact test was used to compare the
ORIGINAL ARTICLE Gomes da Silva et al. 627
differences of syndecan-1 expression in the histologic components of each tumor group; the t test was used to compare the mean Ki-67 labeling indexes. The current study was a retrospective study; no patients were interviewed or examined. All information was retrieved from laboratory records and from histologic analysis of the slides. We followed the Helsinki Declaration for the study of human participants.
RESULTS The study consisted of 17 (68%) central CCOTs, 4 (16%) central CCOTs associated with odontoma (CCOTos), 2 (8%) peripheral CCOTs (CCOTps), 1 (4%) central DGCT, and 1 (4%) central GCOC. Apart from the 4 CCOTos, 1 central CCOT was associated with an ameloblastic fibroma in the posterior mandible of a 17-year-old girl. The mean age of the patients was 27.1 years (standard deviation [SD], 18.1; range, 969 years). The maxilla was slightly more affected than the mandible, and radiolucencies with radiopaque foci presented in 52% of the available images. The detailed distribution of the clinical and radiologic parameters from the 25 studied tumors is included in Table I. The mean radiologic diameter of the tumors was 43.8 mm (SD, 22.8; range, 15-80 mm), and the time of complaint reported by the patients showed a mean of 36.6 months (SD, 56.5; range, 1-180 months). Histologic analysis of the tumors found that, apart from the typical morphologic features related to each subtype, ghost cells and calcifications were prominent in 44% and 32% of the cases, respectively. Focal ameloblastomatous proliferations and islands of odontogenic remnants in the fibrous capsule were observed in 60% and 68% of the cases, respectively. Ameloblastomatous proliferation was a prominent feature in CCOTps, the DGCT, and the GCOC, but it was not observed in CCOTos. Dentinoid material was a prominent feature in 9 tumors (36%). The GCOC showed tumor cells with enlarged nuclei and decreased nuclearcytoplasm ratio, prominent nucleoli, foci of necrosis, and hemorrhage in selected areas. Table II summarizes the distribution of histologic features observed in each specific entity, and Figure 1 shows representative histologic features from select tumors. Considering the histologic components found in all tumors, basal cells (defined as the cells located in the first epithelial layer, in direct contact with basal lamina/ connective tissue) and cells resembling the stellate reticulum expressed syndecan-1 in 36% and 72% of the cases, respectively (Figure 2, A). The staining patterns seen in ghost cells and calcifications were not considered positive, because they were not membranous like the pattern visualized in other cell types (see
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Table I. Clinical and radiologic data according to final diagnosis
Parameter
Calcifying cystic Calcifying cystic Calcifying cystic odontogenic tumor þ odontogenic tumor, Dentinogenic Ghost cell odontogenic tumor odontoma peripheral ghost cell tumor odontogenic carcinoma Total
Age (y) Up to 20 >21 Not available Gender Male Female Location Maxilla Mandible Radiologic image Radiolucency Radiolucency/radiopacity Not available Impacted tooth Absent Present
8 9 d
1 2 1
d 2 d
1 d d
d 1 d
10 14 1
8 9
3 1
1 1
1 d
1 d
14 11
10 7
3 1
d 2
d 1
1 d
14 11
8 7 2
d 4 d
1 d d
1 d d
10 11 2
9 8
2 2
d 1
1 d
14 11
Not applicable Not applicable Not applicable 2 d
Table II. Histologic features according to final diagnosis
Histologic features Ghost cells Focal Prominent Ameloblastomatous proliferation Absent Present Calcification Not prominent Prominent Epithelial odontogenic remnants in the fibrous capsule Absent Present Dentinoid material Absent/Not prominent Prominent
Calcifying cystic Calcifying cystic Calcifying cystic Dentinogenic Ghost cell odontogenic odontogenic odontogenic ghost odontogenic tumor tumor þ odontoma tumor, peripheral cell tumor carcinoma Total 11 6
2 2
d 2
1 d
d 1
14 11
6 11
4 d
d 2
d 1
d 1
10 15
11 6
3 1
1 1
1 d
1 d
17 8
3 14
3 1
1 1
1 d
d 1
8 17
12 5
3 1
d 2
1 d
d 1
16 9
Figure 2, B). Syndecan-1 expression in epithelial odontogenic remnants in the capsule and ameloblastomatous proliferations was evaluated only in the cases presenting these features and revealed immunopositivity in 10 of 17 cases (59%) and in 9 of 15 cases (60%), respectively (see Figure 2, C, D). Analysis of the fibrous capsule found that syndecan-1-positive stromal spindle cells were found in 68% of the cases (see Figure 2, E). Additionally, syndecan-1-labeled plasma cells were present in the connective tissue of the capsule in 7 cases (28%). A strong labeling pattern of syndecan-1 expression was observed in superficial stromal spindle cells of the capsule in several regions of all tumor groups, except for the GCOC (see Figure 2, F). Syndecan-1 expression was observed in basal cells
that were located in 35% of the CCOTs, 100% of the CCOTps and the GCOC, and 0% of the CCOTos and the DGCT (P ¼ .086). Syndecan-1 was frequently expressed in the cells resembling the stellate reticulum and ameloblastomatous proliferation in the majority of the tumor groups (CCOT, DGCT, and GCOC) (Table III). The Ki-67 labeling index showed a mean of 4.1% (range, 0%-49.3%) per high-power field (Figure 3, A, B). The Ki-67 labeling index for each specific histologic subtype was 2.2% for CCOTs, 7.1% for CCOTps, and 49.3% for the GCOC. There were no Ki-67-labeled cells in the CCOTos or the DGCT. The mean Ki-67 labeling index was higher in cases that displayed ameloblastomatous proliferations (6.5 vs 0.17 in cases
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ORIGINAL ARTICLE Gomes da Silva et al. 629
Fig. 1. A, Typical histologic features of a calcifying cystic odontogenic tumor showing the epithelial lining that contains basal cells, cells resembling the stellate reticulum, and ghost cells (hematoxylin-eosin, original magnification 40). B, Calcifying cystic odontogenic tumor showing ghost cells, a cystic area, and an ameloblastomatous proliferation on the fibrous capsule (hematoxylineosin, original magnification 10). C, Detail of an area predominantly composed of ghost cells and calcification foci (hematoxylineosin, original magnification 10). D, Ghost cell odontogenic carcinoma showing hyperchromatic epithelial cells, abundant ghost cells, and hemorrhage (hematoxylin-eosin, original magnification 10).
with no proliferations; P ¼ .142) and prominent ghost cells (7.5 vs 1.27 in cases with focal ghost cells; P ¼ .136), but the differences were not statistically significant. The majority of cases, except for the GCOC, presented very low proliferative indexes; therefore, it was not possible to correlate these values with any of the studied parameters. Figure 4 shows a comparison of histologic features and syndecan-1 and Ki-67 expression levels in CCOT and GCOC.
DISCUSSION CCOTs, DGCTs, and GCOCs are well-characterized entities, and the clinical and radiologic features of the tumors included in the present study reinforce previously reported data.4-6,10-16 However, apart from their specific microscopic diagnostic criteria, they can share common histologic characteristics, including cells resembling the stellate reticulum of the enamel organ, basal polarized columnar to cuboidal cells, and ghost cells, as also exemplified by the present results. In epithelial tissue, syndecan-1 has been associated with binding to proteins of the extracellular matrix, mediating epithelial-stromal interactions and cell proliferation.7 Some studies have found controversial results regarding the role of syndecan-1 expression and the biologic behavior of select tumors, including their invasive capacity.7 Downregulation of syndecan-1 in
epithelial tumor cells and the alteration of its expression from epithelial tumor cells to stromal cells and extracellular matrix have been implicated in tumor invasiveness.7 Loss of syndecan-1 expression by epithelial cells has been associated with a poor prognosis in endometrial, lung, gastric, colorectal, and oral cancers, and increased syndecan-1 expression in tumor cells can be associated with a poor prognosis in breast carcinomas.8,17,18 Increased stromal expression of syndecan-1 has been associated with a poor prognosis in endometrial, gastric, ovarian, breast, and oral cancers.17,18 The mechanisms involved in these processes remain unknown, but it has been suggested that syndecan-1 expression by fibroblasts creates a favorable environment for tumor growth because this molecule binds to several epithelial mitogens, including hepatocyte and epidermal growth factors.19 Syndecan-1 expression in odontogenic cysts and OTs has been previously reported, and results have suggested a possible prognostic significance of this molecule in these entities. Decreased expression of syndecan-1 was observed in solid ameloblastomas compared with unicystic ameloblastomas; additionally, recurrent ameloblastomas showed decreased syndecan1 expression compared with nonrecurrent ameloblastomas, suggesting that decreased syndecan-1 expression may be associated with increased
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Fig. 2. A, Prominent syndecan-1 expression in cells resembling the stellate reticulum and focal syndecan-1 expression in basal cells in a calcifying cystic odontogenic tumor (immunoperoxidase, 40). B, Cytoplasmic syndecan-1 expression in ghost cells in a calcifying cystic odontogenic tumor (arrow, upper left corner) (immunoperoxidase, 40). C, Syndecan-1 expression in odontogenic epithelial remnants in a calcifying cystic odontogenic tumor (immunoperoxidase, 40). D, Syndecan-1 expression in ameloblastomatous proliferations on the capsule in a calcifying cystic odontogenic tumor (immunoperoxidase, 40). E, Syndecan-1 expression in the epithelial component and superficial stromal cells in a calcifying cystic odontogenic tumor (immunoperoxidase, 10). F, Absence of syndecan-1 expression in stromal cells in a ghost cell odontogenic carcinoma (immunoperoxidase, 10).
aggressiveness of these tumors.8,20 Expression of syndecan-1 has also been found to be decreased in ameloblastic carcinomas compared with peripheral ameloblastomas and desmoplastic ameloblastomas.21 Additionally, decreased expression of syndecan-1 has been found in ameloblastomas compared with keratocystic odontogenic tumors and dentigerous cysts.20 Syndecan-1 has been found to be expressed in ameloblasts, cuboidal cells, and squamous areas in ameloblastomas; in the stromal component, it has been found to be weak in stromal spindle cells but strong in the extracellular matrix and basal membrane, supporting that this molecule can be associated with their invasiveness.7 Syndecan-1 was identified in odontogenic
epithelium and granular cells in central granular cell OTs, suggesting an important role in cell-cell adhesion and reciprocal interaction between these cells.22 High syndecan-1 expression was observed in the epithelial lining of radicular and dentigerous cysts and keratocystic odontogenic tumors.9 Nevertheless, expression of syndecan-1 has not been previously studied in CCOTs, DGCTs, and GCOCs. As shown in Table III, syndecan-1 expression was identified in almost all cellular components from the 5 studied groups. Cells resembling the stellate reticulum, ameloblastomatous proliferations, and odontogenic epithelial remnants expressed syndecan-1 more frequently than basal cells. Although there were some
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ORIGINAL ARTICLE Gomes da Silva et al. 631
Table III. Distribution of syndecan-1 expression in each histologic component according to final diagnosis
Histologic component Basal cells Cells resembling stellate reticulum Spindle cells in the capsule Odontogenic epithelial remnants Ameloblastomatous proliferation
Calcifying cystic Calcifying cystic Ghost cell Calcifying cystic odontogenic tumor þ odontogenic tumor, Dentinogenic odontogenic odontogenic tumor odontoma peripheral ghost cell tumor carcinoma
Total
P
6/17 (35%) 11/17 (65%)
0/4 (0%) 3/4 (75%)
2/2 (100%) 2/2 (100%)
0/1 (0%) 1/1 (100%)
1/1 (100%) 9/25 (36%) .086 1/1 (100%) 18/25 (72%) .732
13/17 (77%) 9/14 (64%)
1/4 (25%) 1/1 (100%)
2/2 (100%) 0/1 (0%)
1/1 (100%) 0/0 (0%)
0/1 (0%) 0/1 (0%)
6/11 (55%)
0/0 (0%)
1/2 (50%)
1/1 (100%)
1/1 (100%)
17/25 (68%) .112 10/17 (59%) .292 9/15 (60%) .670
Fig. 3. Ki-67 expression in calcifying cystic odontogenic tumor (A, immunoperoxidase, 40; B, immunoperoxidase, 100).
Fig. 4. A-C, Calcifying cystic odontogenic tumor. A, Typical histologic features (hematoxylin-eosin, original magnification 40). B, Syndecan-1 expression mostly in cells that resemble stellate reticulum and stromal cells (immunoperoxidase, 40). C, Focal Ki-67 expression (immunoperoxidase, 40). D-F, Ghost cell odontogenic carcinoma. D, Characteristic histologic features (hematoxylin-eosin, original magnification 40). E, Syndecan-1 expression in hyperchromatic tumor cells (immunoperoxidase, 40). F, Ki-67 expression in approximately half of the tumor cells (immunoperoxidase, 40).
differences in the number of tumors expressing syndecan-1 in each histologic component, statistically significant differences were not encountered. Basal cells expressed syndecan-1 in approximately one-third of the
cases, contrary to what has been previously reported for odontogenic cystic lesions.9 In contrast, in some areas, a strong labeling pattern of syndecan-1 expression was observed in superficial stromal cells of the capsule,
ORAL AND MAXILLOFACIAL PATHOLOGY 632 Gomes da Silva et al.
possibly representing undifferentiated mesenchymal cells, fibroblasts, or myofibroblasts. Although the present study included only 1 GCOC, no evidence of stromal syndecan-1 expression was observed in this specific case. In previous reports, syndecan-1 expression in ameloblastomas was higher in cells resembling the stellate reticulum than in ameloblasts.20 Similarly, our results showed higher syndecan-1 expression in cells resembling the stellate reticulum in CCOTs, DGCTs, and GCOCs. In the current study, the majority of cases showing odontogenic epithelial remnants and ameloblastomatous proliferation on the capsule also showed an intense syndecan-1 staining in the proliferative areas, unlike the expression in basal cells; the significance of this expression pattern has not been elucidated. It seems that both decreased epithelial syndecan-1 expression and increased stromal syndecan-1 expression are common features in CCOTs, DGCTs, and GCOCs. The Ki-67 labeling index has been frequently used to estimate the cellular proliferative capacity in both benign and malignant tumors, including OTs and, more specifically, ghost cellecontaining OTs.6,16 In previous reports, the Ki-67 labeling index was very low or even absent, except for select DGCTs and all GCOCs.6,16 As expected, in the current study, the Ki-67 labeling index was prominent in the GCOC and, surprisingly, it was also relatively high in CCOTps, but it was not observed in the DGCT. Both CCOTps included in the present study presented a prominent inflammatory infiltrate, and this would have influenced the proliferative indexes found in these tumors. Additionally, cases presenting ameloblastomatous proliferation showed a higher mean Ki-67 labeling index, although the difference was not statistically significant compared with cases without this histologic feature.
CONCLUSION Syndecan-1 was mostly expressed in cells resembling stellate reticulum and stromal cells from the fibrous capsule, especially in the DGCT and the CCOTs; in contrast, syndecan-1 expression in basal cells was found in approximately one-third of the cases. Therefore, our results show that syndecan-1 expression is variable in cells resembling the stellate reticulum, stromal cells, and basal cells in ghost cellecontaining OTs. Given that it is accepted that the behavior of CCOTs, DGCTs, and GCOCs is distinct, the differential expression of proteoglycans associated with cell adhesion and growth factor signaling could at least partially be associated with these characteristics. REFERENCES 1. Gorlin RJ, Pindborg JJ, Clausen FP, Vickers RA. The calcifying odontogenic cystda possible analogue of the cutaneous
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OOOO Volume 117, Number 5 20. Al-Otaibi O, Khounganian R, Anil S, Rajendran R. Syndecan-1 (CD138) surface expression marks cell type and differentiation in ameloblastoma, keratocystic odontogenic tumor and dentigerous cyst. J Oral Pathol Med. 2013;42:186-193. 21. Bologna-Molina R, Mosqueda-Taylor A, Lopez-Corella E, et al. Comparative expression of syndecan-1 and Ki-67 in peripheral and desmoplastic ameloblastomas and ameloblastic carcinoma. Pathol Int. 2009;59:229-233. 22. Mesquita AT, Santos CR, Gomez RS, Jorge J, Léon JE, de Almeida OP. Central granular cell odontogenic tumor: a histopathologic and immunohistochemical study. Ann Diagn Pathol. 2009;13:405-412.
ORIGINAL ARTICLE Gomes da Silva et al. 633 Reprint requests: Fábio Ramôa Pires, DDS, PhD Department of Oral Pathology School of Dentistry State University of Rio de Janeiro Boulevard 28 de Setembro, 157 Vila Isabel 20551-030 Rio de Janeiro, RJ Brazil [email protected]
