Hum Genet (1991) 88:39-41
9 Springer-Verlag 1991
Chromosomal instability in breast cancer patients Leonardo Barrios 1, M. R. Caballin 2' 3, R o s a Mir6 I, 2, Carme Fuster 1, Ferr~n Guedea 4, Antoni Subias 4, and Josep Egozcue 1'2 1Department de Biologia Cel.lular i Fisiologia, 2Institut de Biologia Fonamental "Vicent Villar Palasf", 3Department de Biologia Animal, Vegetal i Ecologia, and 4Servei d'Oncologia, Hospital de la Santa Creu i Sant Pau, Universitat Autbnoma de Barcelona, E-08193 Bellaterra (Barcelona), Spain Received September 25, 1989 / Revised June 24, 1991
Summary. W e have carried out cytogenetic studies, using the G-banding technique, in peripheral blood lymphocytes of 10 patients affected by breast carcinoma. The frequency of aberrant m e t a p h a s e s (7.36%) is significantly different f r o m that of o u r l a b o r a t o r y controls (3.76% of aberrant metaphases) but not f r o m that detected in patients suffering from b l a d d e r cancer (10.64%) and Hodgkin's disease (11.03%), two conditions that have previously b e e n described as c h r o m o s o m a l l y unstable. O u r results suggest that breast carcinoma patients show a degree of c h r o m o s o m a l instability that could be related to a predisposition to neoplastic disease.
Introduction The relationship between the presence of a high frequency of c h r o m o s o m a l aberrations and a predisposition to cancer has b e e n well established in the so-called chromosomal instability syndromes (ataxia telangiectasia, Fanconi's a n a e m i a and B l o o m ' s syndrome). C h r o m o somal instability, although with a lower frequency, is also present in peripheral b l o o d lymphocytes of patients affected by s o m e types of cancer, such as retinoblastoma (Czeizel et al. 1974; T a k a b a y a s h i et al. 1983; de Nufiez et al. 1984), renal carcinoma ( W a n g et al. 1982), skin cancers (Nordenson et al. 1984), patients with primary neoplasias (Brown et al. 1985), pre-cancerous and cancerous lesions of the cervix uteri (Murty et al. 1985), familial polyposis of the colon ( D e l h a n t y et al. 1983), H o d g k i n ' s disease (Barrios et al. 1988), bladder cancer (Barrios et al. 1990), and in o n e case of breast carcinoma (Madhavi et al. 1990). F u r t h e r m o r e , Wurster-Hill et al. (1974, 1979) have observed an increased frequency of structural c h r o m o s o m a l aberrations in families with a high incidence of neoplasias, affecting b o t h cancer patients and individuals with no evidence of malignancy. Taking into account the familial c o m p o n e n t observed in breast carcinoma, c h r o m o s o m a l instability could also Offprint requests to: L. Barrios
be expected in these patients. W e present here a cytogenetic study, using G-banding, carried out on the peripheral blood lymphocytes of 10 untreated patients affected by breast carcinoma.
Materials and methods The subjects of this study were 10 patients affected by breast carcinoma. All of them were untreated at the time of examination. Clinical data are shown in Table 1. For comparison, 10 normal individuals with ages ranging from 21 to 42 years were studied under the same experimental conditions. Peripheral blood samples were cultured for 72 h in HAM's F-10 medium supplemented with 20% fetal calf serum and 5% (0.06 gg/ ml) phytohaemagglutinin. Colcemid (0.06 ~tg/ml) was added 30 min before harvesting. G-banding techniques were applied to identify chromosomal aberrations.
Results The frequency and types of c h r o m o s o m a l aberrations observed in the controls and in the untreated breast carcinoma patients are shown in T a b l e 2. T h e frequency of
Table 1. Clinical data of individuals affected by breast carcinoma Case
Age
Familial antecedents
1 2 3 4 5 6 7 8 9 10
40 42 61 37 62 42 46 56 59 70
+ Yesa + Yesa + Yesa + Yesb + Yesb - No - No - No - No - No
a Breast cancer in direct relatives b Other types of cancer than breast carcinoma
40 Table 2. Frequency and types of chromosomal alterations in peripheral blood lymphocytes Controls
Breast carcinoma
No. of subjects/metaphases Aberrant metaphases (%)
10/1141 43 (3.76%)
10/448 33 (7.36%)
Total abnormalities
49
50
Structural abnormalities
Translocations (%) Dicentrics (%) Deletions (%) Acentric fragments (%) Marker chromosomes (%) Inversions (%)
2 2 1 1 -
(4.08%) (4.08%) (2.04%) (2.04%)
9 (18%) 7 (14%) 5 (10%) 2 (4%) 6 (12%) 2 (4%)
Subtotal (%)
6 (12.24%)
31 (62%)
Chromatid gaps (%) Chromosome gaps (%) Chromatid breaks (%) Chromosome breaks (%)
13 (26.53%) 7 (14.28%) 5 (10.20%) 11 (22.45%)
3 (6%) 1 (2%) 4 (8%)
Subtotal (%)
36 (73.46%)
8 (16%)
Trisomies and tetrasomies (%) Polyploidies (%)
7 (14.28%) -
10 (20%) 1 (2%)
Subtotal (%)
7 (14.28%)
11 (22%)
Numerical abnormalities
A
B
Fig. 1A, B. Partial karyotypes showing structural chromosomal abnormalities (arrows) observed in lymphocytes from breast carcinoma patients. A Inv (7)(p15q36) observed in one cell from case 5. B Del (11)(p14) observed in one cell from case 3
metaphases with chromosomal alterations were 3.76% and 7.36%, respectively. Of the total number of chromosomal aberrations in breast cancer patients, 62% corresponded to major structural chromosomal abnormalities (translocations, deletions, inversions, etc.; Fig. 1), whereas 16% were gaps or breaks. Numerical abnormalities represented 22% of the total. It is interesting to note that, in one case, we found a tetraploid metaphase with multiple repeated alterations. The chromosomal abnormalities of this metaphase have not been taken into account. None of the chromosomal alterations was found repeated in the same patient or found in different individuals, with the exception of case 7 who had 3 metaphases with X trisomy among the 102 metaphases analysed. This alteration was also observed in one metaphase of cases 1 and 6 (Fig. 2). In relation to the frequency of aberrant metaphases, we did not find significant differences between premenopausal (cases 1, 2, 4, 6 and 7) and postmenopausal (cases
Fig. 2. Metaphase from case 6 showing an X trisomy
Table 3. Number of structural and numerical alterations per cell
Major structural abnormalities/ceU Gaps and breaks/cell Numerical abnormalities/cell Total abnormalities/cell
Controls
Breast cancer patients
0.0052 0.0315 0.0061 0.0429
0.0691 0.0178 0.0245 0.1116
3, 5, 8, 9 and 10) breast cancer patients. Significant differences were not found when a comparison was made between breast carcinoma patients with (cases i, 2, 3, 4 and 5) and without (cases 6, 7, 8, 9 and 10) familial antecedents. Likewise, breast carcinoma patients with familial antecedents of breast carcinoma (cases 1, 2 and 3) did not show significant differences from breast carcinoma patients with familial antecedents of types of cancer other than breast carcinoma (cases 4 and 5). When a comparison is made between breast carcinoma patients and controls, it can be seen that the frequency of aberrant metaphases is statistically different. Moreover, the number of cells with major structural chromosomal aberrations is significantly higher in breast carcinoma patients (20 out of 448 cells) than in controls (6 out of 1141 cells) (P < 10-6). The number of gaps and breaks per cell in the controis was higher than in the breast cancer patients, although the number of major structural alterations and numerical abnormalities per cell was lower (Table 3). It is interesting to note that 6 out of the 7 trisomies observed in the controls were found in metaphases of the same individual (aged 42), and that 4 of them were X trisomy. Of the 40 breakpoints clearly identified in structural chromosome aberrations from breast carcinoma patients, eight were on chromosome 1, six on chromosome 7, five on the X chromosome, and three on chromosomes 11 and 16. The other chromosomes implicated in structural chromosomal aberrations had only one or two breakpoints. The chromosome bands most involved in breakpoints were Xp22 (three times), lp22, lq32, 7 p l l , 11p14 and 16q21 (twice).
41
Discussion
References
The results presented here show that the percentages of aberrant m e t a p h a s e s in breast cancer patients are significantly higher than those of o u r controls. If we assume that there is a continuous degree of c h r o m o s o m a l instability in h u m a n populations ( H s u 1983), it could be suggested that breast cancer patients show a degree of chrom o s o m e instability lower than that found in bladder cancer (Barrios et al. 1990) and H o d g k i n ' s disease patients (Barrios et al. 1988). The higher n u m b e r of major structural c h r o m o s o m a l aberrations per cell in breast carcinoma patients (0.0691) than in controls (0.0052), and the significantly higher n u m b e r of cells with m a j o r structural c h r o m o s o m a l aberrations in these patients support this hypothesis. H o w e v e r , a possible increase in chromosomal instability induced by the presence of the tumour cannot be disregarded as suggested by Nordenson et al. (1984). Recently, Madhavi et al. (1990) have described a reduction in the frequency of c h r o m o s o m a l abnormalities after removal of the t u m o u r from a 14-year-old breast carcinoma patient. C h r o m o s o m e s 1, 7, 16 and 11 were a m o n g the most frequently implicated in structural c h r o m o s o m a l abnormalities, and have been described as preferentially involved in chromosomal abnormalities in breast carcinoma cells (Pathak and G o o d a c r e 1986; H e i m and Mitelman 1987; Dutrillaux et al. 1990; Geleick et al. 1990; FertiPassantonopoulou et al. 1991). Although it is difficult to establish a relationship between the c h r o m o s o m a l alterations detected by us in lymphocytes and those described in t u m o u r cells, the coincidence of the c h r o m o s o m e s implicated could indicate that the c h r o m o s o m e instability in these patients preferentially affects these c h r o m o s o m e s . Likewise, it is interesting to note that the c h r o m o s o m e band most involved in the c h r o m o s o m a l a b e r r a t i o n s was Xp22, and that, of the 10 trisornies o b s e r v e d in lymphocytes, five were X trisomy (three in patient 7 and one in patients 1 and 6, all of w h o m were b e t w e e n 40 and 46 years of age). Cells with aneuploidies of the X c h r o m o s o m e , both 45 X and 47 X X X , increase with age, particularly above the age of 60 (Fitzgerald 1983). Patients 1, 6 and 7 could be X X / X X X mosaics, although an elevated incidence of breast cancer has not b e e n d e m o n s t r a t e d for X X / X X X females. A n increased incidence of this kind of t u m o u r has been described in X X Y males. Recently, Wang et al. (1990) have found two active X c h r o m o s o m e s in breast carcinoma cell lines; these arose as a result of the duplication or nondisjunction of the active X c h r o m o s o m e and the loss of the inactive X c h r o m o s o m e . These results taken together with ours indicate that the X chromosome plays a role in breast cancer.
Barrios L, Caballin MR, Mir6 R, Fuster C, Berrozpe G, Subias A, Batlle X, Egozcue J (1988) Chromosome abnormalities in peripheral blood lymphocytes from untreated Hodgkin's patients. A possible evidence for chromosome instability. Hum Genet 78: 320-324 Barrios L, Mir6 R, Caballin MR, Fuster C, Guedea F, Subias A, Egozcue J (1990) Chromosome instability in bladder carcinoma patients. Cancer Genet Cytogenet 49:107-111 Brown T, Dawson AA, McDonals IA, Bullock I, Watt JL (1985) Chromosome damage and sister chromatid exchanges in lymphocyte cultures from patients with two primary cancers. Cancer Genet Cytogenet 17: 35-42 Czeizel A, Crosz L, Gardonyi J, Remenar K, Ruziscka P (1974) Chromosome studies in twelve patients with retinoblastoma. Humangenetik 22:159-166 Delhanty JDA, Davis MB, Wood J (1983) Chromosomal instability in lymphoeytes, fibroblasts and colon epithelial-hke cells from patients with familial polyposis coll. Cancer Genet Cytogenet 8: 27-50 Dutrillaux B, Gerbault-Sereau M, Zafrani B (1990) Characterization of chromosomal anomalies in human breast cancer. Cancer Genet Cytogenet 49: 203-217 Ferti-Passantonopoulou A, Panani AD, Raptis S (1991) Preferential involvement of 11q23-24 and 11p15 in breast cancer. Cancer Genet Cytogenet 51:183-188 Fitzgerald PA (1983) Premature centromere division of the X chromsome. In: Sandberg AA (ed) Cytogenetics of the mammalian X chromosome. In: Sandberg AA (ed) Cytogeneties of the mammalian X chromosome, part A: Basic mechanisms of X chromosome behavior. Liss, New York, pp 171-184 Geleick D, Miiller H, Matter A, Torhorst J, Regenass U (1990) Cytogenetics of breast cancer. Cancer Genet Cytogenet 46: 217-229 Heim S, Mitelman F (1987) Cancer cytogenetics. Liss, New York Hsu TC (1983) Genetic instability in the human population: a working hypothesis. Hereditas 98:1-9 Madhavi R, Guntur M, Ghosh R, Gosh PK (1990) Double minute chromosomes in the leukocytes of a young girl with breast carcinoma. Cancer Genet Cytogenet 44:203-207 Murty VVVS, Mitra AB, Luthra UK (1985) Spontaneous chromosomal aberrations in patients with precancerous and cancerous lesions of the cervix uteri. Cancer Genet Cytogenet 17:347354 Nordenson I, Beckman K, Liden S, Stjernberg N (1984) Chromosomal aberrations and cancer risk. Hum Hered 34: 76-81 Nufiez M de, Penehaszaden LIB, Pimentel E (1984) Chromosome fragility in patients with sporadic unilateral retinoblastoma. Cancer Genet Cytogenet 11 : 139-141 Pathak S, Goodaere A (1986) Specific chromosome anomalies and predisposition to human breast, renal ceil, and colorectal carcinoma. Cancer Genet Cytogenet 19: 29-36 Takabayashi T, Lin MS, Wilson MG (1983) Sister chromatid exchanges and chromosome aberrations in fibroblasts from patients with retinoblastoma. Hum Genet 63: 317-319 Wang N, Kantor A, Soldat K, Linluist K, Strand R, McLanglalin H, Schuman L (1982) Higher frequency of chromosomal aberrations and polimorphism in patients with renal carcinoma. Am J Hum Genet 34: 78A Wang N, Cedrone E, Skuse GR, Insel R, Dry J (1990) Two identical active X chromosomes in human mammary carcinoma cells. Cancer Genet Cytogenet 46: 271-280 Wurster-Hill DH, Cornwell GG, McIntyre OR (1974) Chromosomal aberrations and neoplasm - a family study. Cancer 33: 72-81 Wurster-Hiil DH, Cornwell GG, McIntyre OR (1979) Chromosome aberrations of myeloid and lymphoid cells in cancer patients and family members without evidence of cancer. Cancer Detect Prev 2:125-126
Acknowledgements. This investigation received financial support from CAICYT (pr. no. 0699-84) and CIRIT. We want to thank C. Preciado (grant from CIRIT) for technical assistance.
9 Springer-Verlag 1991
Chromosomal instability in breast cancer patients Leonardo Barrios 1, M. R. Caballin 2' 3, R o s a Mir6 I, 2, Carme Fuster 1, Ferr~n Guedea 4, Antoni Subias 4, and Josep Egozcue 1'2 1Department de Biologia Cel.lular i Fisiologia, 2Institut de Biologia Fonamental "Vicent Villar Palasf", 3Department de Biologia Animal, Vegetal i Ecologia, and 4Servei d'Oncologia, Hospital de la Santa Creu i Sant Pau, Universitat Autbnoma de Barcelona, E-08193 Bellaterra (Barcelona), Spain Received September 25, 1989 / Revised June 24, 1991
Summary. W e have carried out cytogenetic studies, using the G-banding technique, in peripheral blood lymphocytes of 10 patients affected by breast carcinoma. The frequency of aberrant m e t a p h a s e s (7.36%) is significantly different f r o m that of o u r l a b o r a t o r y controls (3.76% of aberrant metaphases) but not f r o m that detected in patients suffering from b l a d d e r cancer (10.64%) and Hodgkin's disease (11.03%), two conditions that have previously b e e n described as c h r o m o s o m a l l y unstable. O u r results suggest that breast carcinoma patients show a degree of c h r o m o s o m a l instability that could be related to a predisposition to neoplastic disease.
Introduction The relationship between the presence of a high frequency of c h r o m o s o m a l aberrations and a predisposition to cancer has b e e n well established in the so-called chromosomal instability syndromes (ataxia telangiectasia, Fanconi's a n a e m i a and B l o o m ' s syndrome). C h r o m o somal instability, although with a lower frequency, is also present in peripheral b l o o d lymphocytes of patients affected by s o m e types of cancer, such as retinoblastoma (Czeizel et al. 1974; T a k a b a y a s h i et al. 1983; de Nufiez et al. 1984), renal carcinoma ( W a n g et al. 1982), skin cancers (Nordenson et al. 1984), patients with primary neoplasias (Brown et al. 1985), pre-cancerous and cancerous lesions of the cervix uteri (Murty et al. 1985), familial polyposis of the colon ( D e l h a n t y et al. 1983), H o d g k i n ' s disease (Barrios et al. 1988), bladder cancer (Barrios et al. 1990), and in o n e case of breast carcinoma (Madhavi et al. 1990). F u r t h e r m o r e , Wurster-Hill et al. (1974, 1979) have observed an increased frequency of structural c h r o m o s o m a l aberrations in families with a high incidence of neoplasias, affecting b o t h cancer patients and individuals with no evidence of malignancy. Taking into account the familial c o m p o n e n t observed in breast carcinoma, c h r o m o s o m a l instability could also Offprint requests to: L. Barrios
be expected in these patients. W e present here a cytogenetic study, using G-banding, carried out on the peripheral blood lymphocytes of 10 untreated patients affected by breast carcinoma.
Materials and methods The subjects of this study were 10 patients affected by breast carcinoma. All of them were untreated at the time of examination. Clinical data are shown in Table 1. For comparison, 10 normal individuals with ages ranging from 21 to 42 years were studied under the same experimental conditions. Peripheral blood samples were cultured for 72 h in HAM's F-10 medium supplemented with 20% fetal calf serum and 5% (0.06 gg/ ml) phytohaemagglutinin. Colcemid (0.06 ~tg/ml) was added 30 min before harvesting. G-banding techniques were applied to identify chromosomal aberrations.
Results The frequency and types of c h r o m o s o m a l aberrations observed in the controls and in the untreated breast carcinoma patients are shown in T a b l e 2. T h e frequency of
Table 1. Clinical data of individuals affected by breast carcinoma Case
Age
Familial antecedents
1 2 3 4 5 6 7 8 9 10
40 42 61 37 62 42 46 56 59 70
+ Yesa + Yesa + Yesa + Yesb + Yesb - No - No - No - No - No
a Breast cancer in direct relatives b Other types of cancer than breast carcinoma
40 Table 2. Frequency and types of chromosomal alterations in peripheral blood lymphocytes Controls
Breast carcinoma
No. of subjects/metaphases Aberrant metaphases (%)
10/1141 43 (3.76%)
10/448 33 (7.36%)
Total abnormalities
49
50
Structural abnormalities
Translocations (%) Dicentrics (%) Deletions (%) Acentric fragments (%) Marker chromosomes (%) Inversions (%)
2 2 1 1 -
(4.08%) (4.08%) (2.04%) (2.04%)
9 (18%) 7 (14%) 5 (10%) 2 (4%) 6 (12%) 2 (4%)
Subtotal (%)
6 (12.24%)
31 (62%)
Chromatid gaps (%) Chromosome gaps (%) Chromatid breaks (%) Chromosome breaks (%)
13 (26.53%) 7 (14.28%) 5 (10.20%) 11 (22.45%)
3 (6%) 1 (2%) 4 (8%)
Subtotal (%)
36 (73.46%)
8 (16%)
Trisomies and tetrasomies (%) Polyploidies (%)
7 (14.28%) -
10 (20%) 1 (2%)
Subtotal (%)
7 (14.28%)
11 (22%)
Numerical abnormalities
A
B
Fig. 1A, B. Partial karyotypes showing structural chromosomal abnormalities (arrows) observed in lymphocytes from breast carcinoma patients. A Inv (7)(p15q36) observed in one cell from case 5. B Del (11)(p14) observed in one cell from case 3
metaphases with chromosomal alterations were 3.76% and 7.36%, respectively. Of the total number of chromosomal aberrations in breast cancer patients, 62% corresponded to major structural chromosomal abnormalities (translocations, deletions, inversions, etc.; Fig. 1), whereas 16% were gaps or breaks. Numerical abnormalities represented 22% of the total. It is interesting to note that, in one case, we found a tetraploid metaphase with multiple repeated alterations. The chromosomal abnormalities of this metaphase have not been taken into account. None of the chromosomal alterations was found repeated in the same patient or found in different individuals, with the exception of case 7 who had 3 metaphases with X trisomy among the 102 metaphases analysed. This alteration was also observed in one metaphase of cases 1 and 6 (Fig. 2). In relation to the frequency of aberrant metaphases, we did not find significant differences between premenopausal (cases 1, 2, 4, 6 and 7) and postmenopausal (cases
Fig. 2. Metaphase from case 6 showing an X trisomy
Table 3. Number of structural and numerical alterations per cell
Major structural abnormalities/ceU Gaps and breaks/cell Numerical abnormalities/cell Total abnormalities/cell
Controls
Breast cancer patients
0.0052 0.0315 0.0061 0.0429
0.0691 0.0178 0.0245 0.1116
3, 5, 8, 9 and 10) breast cancer patients. Significant differences were not found when a comparison was made between breast carcinoma patients with (cases i, 2, 3, 4 and 5) and without (cases 6, 7, 8, 9 and 10) familial antecedents. Likewise, breast carcinoma patients with familial antecedents of breast carcinoma (cases 1, 2 and 3) did not show significant differences from breast carcinoma patients with familial antecedents of types of cancer other than breast carcinoma (cases 4 and 5). When a comparison is made between breast carcinoma patients and controls, it can be seen that the frequency of aberrant metaphases is statistically different. Moreover, the number of cells with major structural chromosomal aberrations is significantly higher in breast carcinoma patients (20 out of 448 cells) than in controls (6 out of 1141 cells) (P < 10-6). The number of gaps and breaks per cell in the controis was higher than in the breast cancer patients, although the number of major structural alterations and numerical abnormalities per cell was lower (Table 3). It is interesting to note that 6 out of the 7 trisomies observed in the controls were found in metaphases of the same individual (aged 42), and that 4 of them were X trisomy. Of the 40 breakpoints clearly identified in structural chromosome aberrations from breast carcinoma patients, eight were on chromosome 1, six on chromosome 7, five on the X chromosome, and three on chromosomes 11 and 16. The other chromosomes implicated in structural chromosomal aberrations had only one or two breakpoints. The chromosome bands most involved in breakpoints were Xp22 (three times), lp22, lq32, 7 p l l , 11p14 and 16q21 (twice).
41
Discussion
References
The results presented here show that the percentages of aberrant m e t a p h a s e s in breast cancer patients are significantly higher than those of o u r controls. If we assume that there is a continuous degree of c h r o m o s o m a l instability in h u m a n populations ( H s u 1983), it could be suggested that breast cancer patients show a degree of chrom o s o m e instability lower than that found in bladder cancer (Barrios et al. 1990) and H o d g k i n ' s disease patients (Barrios et al. 1988). The higher n u m b e r of major structural c h r o m o s o m a l aberrations per cell in breast carcinoma patients (0.0691) than in controls (0.0052), and the significantly higher n u m b e r of cells with m a j o r structural c h r o m o s o m a l aberrations in these patients support this hypothesis. H o w e v e r , a possible increase in chromosomal instability induced by the presence of the tumour cannot be disregarded as suggested by Nordenson et al. (1984). Recently, Madhavi et al. (1990) have described a reduction in the frequency of c h r o m o s o m a l abnormalities after removal of the t u m o u r from a 14-year-old breast carcinoma patient. C h r o m o s o m e s 1, 7, 16 and 11 were a m o n g the most frequently implicated in structural c h r o m o s o m a l abnormalities, and have been described as preferentially involved in chromosomal abnormalities in breast carcinoma cells (Pathak and G o o d a c r e 1986; H e i m and Mitelman 1987; Dutrillaux et al. 1990; Geleick et al. 1990; FertiPassantonopoulou et al. 1991). Although it is difficult to establish a relationship between the c h r o m o s o m a l alterations detected by us in lymphocytes and those described in t u m o u r cells, the coincidence of the c h r o m o s o m e s implicated could indicate that the c h r o m o s o m e instability in these patients preferentially affects these c h r o m o s o m e s . Likewise, it is interesting to note that the c h r o m o s o m e band most involved in the c h r o m o s o m a l a b e r r a t i o n s was Xp22, and that, of the 10 trisornies o b s e r v e d in lymphocytes, five were X trisomy (three in patient 7 and one in patients 1 and 6, all of w h o m were b e t w e e n 40 and 46 years of age). Cells with aneuploidies of the X c h r o m o s o m e , both 45 X and 47 X X X , increase with age, particularly above the age of 60 (Fitzgerald 1983). Patients 1, 6 and 7 could be X X / X X X mosaics, although an elevated incidence of breast cancer has not b e e n d e m o n s t r a t e d for X X / X X X females. A n increased incidence of this kind of t u m o u r has been described in X X Y males. Recently, Wang et al. (1990) have found two active X c h r o m o s o m e s in breast carcinoma cell lines; these arose as a result of the duplication or nondisjunction of the active X c h r o m o s o m e and the loss of the inactive X c h r o m o s o m e . These results taken together with ours indicate that the X chromosome plays a role in breast cancer.
Barrios L, Caballin MR, Mir6 R, Fuster C, Berrozpe G, Subias A, Batlle X, Egozcue J (1988) Chromosome abnormalities in peripheral blood lymphocytes from untreated Hodgkin's patients. A possible evidence for chromosome instability. Hum Genet 78: 320-324 Barrios L, Mir6 R, Caballin MR, Fuster C, Guedea F, Subias A, Egozcue J (1990) Chromosome instability in bladder carcinoma patients. Cancer Genet Cytogenet 49:107-111 Brown T, Dawson AA, McDonals IA, Bullock I, Watt JL (1985) Chromosome damage and sister chromatid exchanges in lymphocyte cultures from patients with two primary cancers. Cancer Genet Cytogenet 17: 35-42 Czeizel A, Crosz L, Gardonyi J, Remenar K, Ruziscka P (1974) Chromosome studies in twelve patients with retinoblastoma. Humangenetik 22:159-166 Delhanty JDA, Davis MB, Wood J (1983) Chromosomal instability in lymphoeytes, fibroblasts and colon epithelial-hke cells from patients with familial polyposis coll. Cancer Genet Cytogenet 8: 27-50 Dutrillaux B, Gerbault-Sereau M, Zafrani B (1990) Characterization of chromosomal anomalies in human breast cancer. Cancer Genet Cytogenet 49: 203-217 Ferti-Passantonopoulou A, Panani AD, Raptis S (1991) Preferential involvement of 11q23-24 and 11p15 in breast cancer. Cancer Genet Cytogenet 51:183-188 Fitzgerald PA (1983) Premature centromere division of the X chromsome. In: Sandberg AA (ed) Cytogenetics of the mammalian X chromosome. In: Sandberg AA (ed) Cytogeneties of the mammalian X chromosome, part A: Basic mechanisms of X chromosome behavior. Liss, New York, pp 171-184 Geleick D, Miiller H, Matter A, Torhorst J, Regenass U (1990) Cytogenetics of breast cancer. Cancer Genet Cytogenet 46: 217-229 Heim S, Mitelman F (1987) Cancer cytogenetics. Liss, New York Hsu TC (1983) Genetic instability in the human population: a working hypothesis. Hereditas 98:1-9 Madhavi R, Guntur M, Ghosh R, Gosh PK (1990) Double minute chromosomes in the leukocytes of a young girl with breast carcinoma. Cancer Genet Cytogenet 44:203-207 Murty VVVS, Mitra AB, Luthra UK (1985) Spontaneous chromosomal aberrations in patients with precancerous and cancerous lesions of the cervix uteri. Cancer Genet Cytogenet 17:347354 Nordenson I, Beckman K, Liden S, Stjernberg N (1984) Chromosomal aberrations and cancer risk. Hum Hered 34: 76-81 Nufiez M de, Penehaszaden LIB, Pimentel E (1984) Chromosome fragility in patients with sporadic unilateral retinoblastoma. Cancer Genet Cytogenet 11 : 139-141 Pathak S, Goodaere A (1986) Specific chromosome anomalies and predisposition to human breast, renal ceil, and colorectal carcinoma. Cancer Genet Cytogenet 19: 29-36 Takabayashi T, Lin MS, Wilson MG (1983) Sister chromatid exchanges and chromosome aberrations in fibroblasts from patients with retinoblastoma. Hum Genet 63: 317-319 Wang N, Kantor A, Soldat K, Linluist K, Strand R, McLanglalin H, Schuman L (1982) Higher frequency of chromosomal aberrations and polimorphism in patients with renal carcinoma. Am J Hum Genet 34: 78A Wang N, Cedrone E, Skuse GR, Insel R, Dry J (1990) Two identical active X chromosomes in human mammary carcinoma cells. Cancer Genet Cytogenet 46: 271-280 Wurster-Hill DH, Cornwell GG, McIntyre OR (1974) Chromosomal aberrations and neoplasm - a family study. Cancer 33: 72-81 Wurster-Hiil DH, Cornwell GG, McIntyre OR (1979) Chromosome aberrations of myeloid and lymphoid cells in cancer patients and family members without evidence of cancer. Cancer Detect Prev 2:125-126
Acknowledgements. This investigation received financial support from CAICYT (pr. no. 0699-84) and CIRIT. We want to thank C. Preciado (grant from CIRIT) for technical assistance.
