Breast Cancer: Role of Sex-Steroid Hormones in Association with e6 and e7 Viral Oncoproteins and their implication as potential Prognostic Marker.
Breast cancer (BC) is the most frequent cancer and second most frequent cause of cancer death among woman. Its development and progression are associated with genetic alterations along with high risk Human Papilloma Virus (HPV) infection and sex-steroid hormones. In present study we have analysed the expression pattern of E6 and E7 HPV oncoproteins along with Estrogens receptor (ER), Progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) expression in Breast Cancer tumor tissue samples from Chittaranjan National Cancer Institute, Kolkata, India and found significant association between the protein expression with development of Breast Cancer. Among the collected samples (N=52), 63% were HPV 16 and 24% were HPV 18 infected. Immunohistochemical analysis of E6 and E7 oncoproteins in BC samples showed 56% and 63% high/medium expression respectively irrespective of Breast Cancer sub typing. ER, PR and HER2 protein expression analysis showed 54%, 35% and 65% high/medium expression in Breast Cancer. Statistical analysis showed significant association between co-expression of viral protein E6 and E7 with ER, PR and HER2 expression pattern. On survivability, patients with both HPV infection and high/medium ER expression showed significantly poor prognosis in comparison to combined HPV infection and PR and HER2 expression pattern. In conclusion, viral oncoprotein and steroid hormones individually play imperative role for development of Breast Cancer but cooperative mechanism of action in these two have more effective functionality in developing the disease.
Keywords - Breast Cancer, Sex-Steroid Hormones, Viral Oncoprotein, Potential Prognostic Marker.