The prognostic role of mitophagy marker Parkin-induced protein kinase 1 in invasive duct carcinoma of the breast: an immunohistochemical study

Abstract

Background The gene Parkin-induced protein kinase 1 (PINK1) encodes a serine/threonine protein kinase associated with mitophagy. It is found in the mitochondria and protects cells against stress-related mitochondrial malfunction. However, its precise function in the development and evolution of tumours, particularly in breast cancer (BC), is yet unknown. PINK1 immunohistochemistry expression in invasive duct BC is the focus of the current study and to link this expression with several clinicopathological criteria, such as patient overall survival. Methods PINK1 monoclonal antibody was used in a retrospective design to immunohistochemistry stain sections from 90 primary invasive duct BC patients and 10 healthy controls. Its association with clinical characteristics was evaluated. Results Positive PINIK1 expression was noticed in 52 (57.5%) of cases. A significant correlation was seen between human epidermal growth factor receptor 2 (HER2) and PINK1 expression ( P =0.05). Positive PINK1 expression was closely linked to cases of HER2 enriched molecular subtype ( P <0.001), multifocal BC ( P =0.03), advanced lymph nodal stage ( P =0.01), and tumour necrosis ( P =0.02) while negative expression was notably connected to luminal BC ( P =0.01). Analysis of Kaplan–Meier survival revealed a significantly better patient overall survival ( P = 0.04) with positive PINK1 immuno-expression and unifocal BC ( P = 0.04), ( P =0.05), respectively. Conclusion The protein linked to mitophagy PINK1 showed significant association regarding criteria of poor prognosis in BC such as HER2 enriched subtype, tumour multifocality, and advanced nodal stage. PINK1 could be a potential target in BC therapy and more research is needed to verify this role.