Cytokine 71 (2015) 66–70
Contents lists available at ScienceDirect
Cytokine journal homepage: www.journals.elsevier.com/cytokine
Clinical significance of serum epidermal growth factor receptor (EGFR) levels in patients with breast cancer Faruk Tas ⇑, Elif Bilgin, Senem Karabulut, Derya Duranyildiz Institute of Oncology, University of Istanbul, Istanbul, Turkey
a r t i c l e
i n f o
Article history: Received 29 July 2014 Received in revised form 28 August 2014 Accepted 1 September 2014
Keywords: Serum EGFR Breast cancer Prognostic factor
a b s t r a c t Epidermal growth factor receptor (EGFR) plays an important role in the pathogenesis of multiple malignancies and its expression strongly also affects the outcomes of cancer patients. The objective of this study was to determine the clinical significance of the serum levels of EGFR in breast cancer (BC) patients. A total of 96 patients with a pathologically confirmed diagnosis of BC were enrolled into this study. Serum EGFR levels were determined by the solid-phase sandwich ELISA method. Age and sex matched 30 healthy controls were included in the analysis. Median age of diagnosis was 48 years old (range: 29–80). Thirty-seven (39%) consisted of metastatic disease. The baseline serum EGFR levels were significantly higher than in the healthy control group (p < 0.001). The serum EGFR concentrations were also significantly higher only in patients with ER-negative and triple-negative tumor (p = 0.05 and p = 0.04, respectively). The other known clinical variables, including grade of histology, stage of disease, serum CA 15.3 levels, and response to chemotherapy were not found to be correlated with serum EGFR concentrations (p > 0.05). Likewise, serum EGFR levels were found to play no prognostic role for survival (p = 0.35). In conclusion, while serum EGFR levels were elevated in BC patients, EGFR level has no predictive and prognostic value in these patients. Ó 2014 Elsevier Ltd. All rights reserved.
1. Introduction Epidermal growth factor receptor (EGFR) is the expression product of oncogene c-erbB1, and it belongs to the human epidermal receptor (HER) family, a structure composed of an extracellular ligand binding domain, a transmembrane lipophilic glycoprotein, and an intracellular tyrosine kinase domain [1–10]. EGFR is widely expressed on the surface of mammalian epithelial cells and other many cell types. Many studies have demonstrated that EGFR has a physiologically favorable role during embryonic and postnatal development. Moreover, EGFR plays an important role in the pathogenesis of multiple malignancies and its expression also strongly affects the outcomes of cancer patients. It has been found to act as a strong prognostic indicator in many cancer types, with increased expression being associated with poor progressionfree or overall survival rates. EGFR is expressed in 20–80% of breast carcinomas and leads to increased uncontrolled growth of cancer cells [1–3,5,6,8]. Expression of EGFR has been shown to be frequently associated with high tumor grade, elevated growth fraction, and inverse relationship ⇑ Corresponding author at: Institute of Oncology, Istanbul University, Capa, 34390 Istanbul, Turkey. Fax: +90 212 534 80 78. E-mail address: [email protected] (F. Tas). http://dx.doi.org/10.1016/j.cyto.2014.09.001 1043-4666/Ó 2014 Elsevier Ltd. All rights reserved.
with estrogen receptor status in breast cancer tissue [1–4,8]. Several analyses examining the prognostic significance of EGFR expression in breast cancer suggest a possibly poor prognosis for patients with EGFR expressed tumors [1,3,5,8]. There exists little information about a possible influence of EGFR expression on response to chemotherapy [2,3]. The extracellular ligand-domains of EGFR can be detected in the bloodstream [3–10]. The extracellular binding region of EGFR is believed to be proteolytically released from the cell surface upon receptor activation and can be accurately quantified in serum via ELISAs [7]. Therefore, a soluble EGFR also can be detected in the serum or plasma of patients with breast cancer. Serum EGFR has been the topic of relatively few reports, and the results from those studies are conflicting [3–10]. It was described that patients with breast cancer showed decreased levels of sEGFR protein compared with healthy control subjects, while others found increased levels or no difference between healthy subjects and patients. Although elevated pretreatment levels have been shown to be associated with decreased survival breast cancer patients, the value of the serum expression of this marker in predicting response to therapies remains largely unclear. Therefore, studies evaluating the clinical relevance of serum EGFR in breast cancer are still lacking. Thus, the significance of the serological levels of EGFR in breast cancer patients is not
F. Tas et al. / Cytokine 71 (2015) 66–70
67
known yet. So, we evaluated the soluble serum levels of EGFR in breast cancer patients consisting of all clinical stages, and assessed associations with the prognosis, various known clinical variables, and response to chemotherapy, in order to examine whether these are potential new biomarkers, for use in the treatment of breast cancer in this study.
the color became yellow. The colored reaction product was measured using an automated ELISA reader (Rayto, RT-1904C Chemistry Analyzer, Atlanta GA, USA) at 450 nm. The results were expressed as ng/mL.
2. Material and methods
Continuous variables were categorized using mean values as cut-off point. Assessment of relationships, comparisons between various clinical/laboratory parameters was accomplished using Mann–Whitney U test. Overall survival was calculated from the date of first admission to the clinics to disease-related death or date of last contact with the patient or any family member. Kaplan–Meier method was used for estimation of survival distribution and differences in survival were assessed by the log-rank statistics. A p value 0.05). The mean follow-up time was 19.4 ± 9.85 months. The mean survival for all patients was 32.7 ± 1.2 months. The 1-, 2-, and 3-year overall survival rates were 92.4% (95% CI = 86.9–97.9), 80.0% (95% CI = 70.2–99.8), and 78.2% (95% CI = 68.4–80.0), respectively. The negativity of ER (p = 0.007) and PR (p = 0.004), elevated serum LDH concentration (p = 0.042), metastatic stage (p < 0.001) and unresponsiveness to chemotherapy (p < 0.001) were statistically significant poor prognostic factors for overall survival (Table 4). However, serum EGFR concentrations were found to have no prognostic role for outcome (p = 0.35) (Table 4 and Fig. 2). 4. Discussion In order to quantify circulating sEGFR using immunoassay methods, serum EGFR protein is being investigated as a potential biomarker for a variety of cancers. Similar to IHC studies of EGFRs, serum sEGFR immunoassay studies may yield different results because of their specific characteristics (e.g., analytical standards, antibody reagents, assay format, and measurement units). To date, several assays have been used to study sEGFR in the serum of breast cancer patients [3–10]. Previous studies have demonstrated that circulating EGFR concentrations may be altered by pathological conditions including breast cancer [3–10]. Serum concentrations of sEGFR have been evaluated in breast cancer patients using ELISA immunoassays [3–10]. These studies showed that serum sEGFR concentrations are lower, higher or similar in breast cancer patients compared
68
F. Tas et al. / Cytokine 71 (2015) 66–70
Table 1 Characteristics of the patient and disease. Variables
n (%)
No. of patients
96 (100)
Age, years
Contents lists available at ScienceDirect
Cytokine journal homepage: www.journals.elsevier.com/cytokine
Clinical significance of serum epidermal growth factor receptor (EGFR) levels in patients with breast cancer Faruk Tas ⇑, Elif Bilgin, Senem Karabulut, Derya Duranyildiz Institute of Oncology, University of Istanbul, Istanbul, Turkey
a r t i c l e
i n f o
Article history: Received 29 July 2014 Received in revised form 28 August 2014 Accepted 1 September 2014
Keywords: Serum EGFR Breast cancer Prognostic factor
a b s t r a c t Epidermal growth factor receptor (EGFR) plays an important role in the pathogenesis of multiple malignancies and its expression strongly also affects the outcomes of cancer patients. The objective of this study was to determine the clinical significance of the serum levels of EGFR in breast cancer (BC) patients. A total of 96 patients with a pathologically confirmed diagnosis of BC were enrolled into this study. Serum EGFR levels were determined by the solid-phase sandwich ELISA method. Age and sex matched 30 healthy controls were included in the analysis. Median age of diagnosis was 48 years old (range: 29–80). Thirty-seven (39%) consisted of metastatic disease. The baseline serum EGFR levels were significantly higher than in the healthy control group (p < 0.001). The serum EGFR concentrations were also significantly higher only in patients with ER-negative and triple-negative tumor (p = 0.05 and p = 0.04, respectively). The other known clinical variables, including grade of histology, stage of disease, serum CA 15.3 levels, and response to chemotherapy were not found to be correlated with serum EGFR concentrations (p > 0.05). Likewise, serum EGFR levels were found to play no prognostic role for survival (p = 0.35). In conclusion, while serum EGFR levels were elevated in BC patients, EGFR level has no predictive and prognostic value in these patients. Ó 2014 Elsevier Ltd. All rights reserved.
1. Introduction Epidermal growth factor receptor (EGFR) is the expression product of oncogene c-erbB1, and it belongs to the human epidermal receptor (HER) family, a structure composed of an extracellular ligand binding domain, a transmembrane lipophilic glycoprotein, and an intracellular tyrosine kinase domain [1–10]. EGFR is widely expressed on the surface of mammalian epithelial cells and other many cell types. Many studies have demonstrated that EGFR has a physiologically favorable role during embryonic and postnatal development. Moreover, EGFR plays an important role in the pathogenesis of multiple malignancies and its expression also strongly affects the outcomes of cancer patients. It has been found to act as a strong prognostic indicator in many cancer types, with increased expression being associated with poor progressionfree or overall survival rates. EGFR is expressed in 20–80% of breast carcinomas and leads to increased uncontrolled growth of cancer cells [1–3,5,6,8]. Expression of EGFR has been shown to be frequently associated with high tumor grade, elevated growth fraction, and inverse relationship ⇑ Corresponding author at: Institute of Oncology, Istanbul University, Capa, 34390 Istanbul, Turkey. Fax: +90 212 534 80 78. E-mail address: [email protected] (F. Tas). http://dx.doi.org/10.1016/j.cyto.2014.09.001 1043-4666/Ó 2014 Elsevier Ltd. All rights reserved.
with estrogen receptor status in breast cancer tissue [1–4,8]. Several analyses examining the prognostic significance of EGFR expression in breast cancer suggest a possibly poor prognosis for patients with EGFR expressed tumors [1,3,5,8]. There exists little information about a possible influence of EGFR expression on response to chemotherapy [2,3]. The extracellular ligand-domains of EGFR can be detected in the bloodstream [3–10]. The extracellular binding region of EGFR is believed to be proteolytically released from the cell surface upon receptor activation and can be accurately quantified in serum via ELISAs [7]. Therefore, a soluble EGFR also can be detected in the serum or plasma of patients with breast cancer. Serum EGFR has been the topic of relatively few reports, and the results from those studies are conflicting [3–10]. It was described that patients with breast cancer showed decreased levels of sEGFR protein compared with healthy control subjects, while others found increased levels or no difference between healthy subjects and patients. Although elevated pretreatment levels have been shown to be associated with decreased survival breast cancer patients, the value of the serum expression of this marker in predicting response to therapies remains largely unclear. Therefore, studies evaluating the clinical relevance of serum EGFR in breast cancer are still lacking. Thus, the significance of the serological levels of EGFR in breast cancer patients is not
F. Tas et al. / Cytokine 71 (2015) 66–70
67
known yet. So, we evaluated the soluble serum levels of EGFR in breast cancer patients consisting of all clinical stages, and assessed associations with the prognosis, various known clinical variables, and response to chemotherapy, in order to examine whether these are potential new biomarkers, for use in the treatment of breast cancer in this study.
the color became yellow. The colored reaction product was measured using an automated ELISA reader (Rayto, RT-1904C Chemistry Analyzer, Atlanta GA, USA) at 450 nm. The results were expressed as ng/mL.
2. Material and methods
Continuous variables were categorized using mean values as cut-off point. Assessment of relationships, comparisons between various clinical/laboratory parameters was accomplished using Mann–Whitney U test. Overall survival was calculated from the date of first admission to the clinics to disease-related death or date of last contact with the patient or any family member. Kaplan–Meier method was used for estimation of survival distribution and differences in survival were assessed by the log-rank statistics. A p value 0.05). The mean follow-up time was 19.4 ± 9.85 months. The mean survival for all patients was 32.7 ± 1.2 months. The 1-, 2-, and 3-year overall survival rates were 92.4% (95% CI = 86.9–97.9), 80.0% (95% CI = 70.2–99.8), and 78.2% (95% CI = 68.4–80.0), respectively. The negativity of ER (p = 0.007) and PR (p = 0.004), elevated serum LDH concentration (p = 0.042), metastatic stage (p < 0.001) and unresponsiveness to chemotherapy (p < 0.001) were statistically significant poor prognostic factors for overall survival (Table 4). However, serum EGFR concentrations were found to have no prognostic role for outcome (p = 0.35) (Table 4 and Fig. 2). 4. Discussion In order to quantify circulating sEGFR using immunoassay methods, serum EGFR protein is being investigated as a potential biomarker for a variety of cancers. Similar to IHC studies of EGFRs, serum sEGFR immunoassay studies may yield different results because of their specific characteristics (e.g., analytical standards, antibody reagents, assay format, and measurement units). To date, several assays have been used to study sEGFR in the serum of breast cancer patients [3–10]. Previous studies have demonstrated that circulating EGFR concentrations may be altered by pathological conditions including breast cancer [3–10]. Serum concentrations of sEGFR have been evaluated in breast cancer patients using ELISA immunoassays [3–10]. These studies showed that serum sEGFR concentrations are lower, higher or similar in breast cancer patients compared
68
F. Tas et al. / Cytokine 71 (2015) 66–70
Table 1 Characteristics of the patient and disease. Variables
n (%)
No. of patients
96 (100)
Age, years
