Caveolin-1 Expression in Benign and Malignant Breast Lesions and Its Correlation with Expression of Estrogen Receptor (ER), Progesterone Receptor (PR), and Human Epidermal Growth Factor Receptor 2 (HER2), Lymph Node Metastasis, Tumor Grade, and Survival of the Patients

 Recent studies have suggested a significant role for Caveolin-1 (CAV1) gene in the pathogenesis of breast carcinomas; however, current evidence is conflicting as some report a tumor suppression effect while others implicate this gene as a promoter of cancer development.

 The present study aimed to provide further evidence on this subject by comparing Caveolin-1 expression between specimens obtained from normal breast tissues, benign lesions and malignant tumors.

 In this cross-sectional study, subjects with specimens resected from their breast tissues for various reasons in Shohadaye-Tajrish Hospital, Tehran, Iran during 2013 were included as the sample population. A total of 100 subjects participated in this survey (53 invasive breast cancer, 26 ductal carcinoma in situ (DCIS), 13 ductal hyperplasia, and 8 normal). Their tissue specimens were prepared and immunohistochemical studies were performed to assess the expression of Caveolin-1, human epidermal growth factor receptor 2 (HER2), estrogen receptor (ER), and progesterone receptor (PR). Correlations between these factors and the survival of patients were assessed using SPSS software.

 Epithelial Caveolin-1 expression was found to have a positive significant correlation with pathology group of the patients (P = 0.039), grade of the tumor (P = 0.032), and lymph node positivity (P = 0.046). A negative correlation was also observed between epithelial Caveolin-1 positivity with HER2 score (P = 0.036) and HER2 positivity (P = 0.012). The overall survival of the patients was negatively affected by epithelial Caveolin-1 expression (28.3 vs. 38.9 months; P = 0.001), grade of the tumor (P < 0.001), and lymph node involvement (34.1 vs. 40.5; P = 0.051), while ER (39.7 vs. 28.9; P = 0.001) and PR (39.6 vs. 31.0; P = 0.010) positivity were associated with improved survival.

 According to the findings, it seems that Caveolin-1 expression might be associated with worse outcomes in patients with breast cancer.