Accumulation of p62 is associated with poor prognosis in patients with triple-negative breast cancer

BACKGROUND: Triple-negative breast cancer (TNBC) is associated with poor prognosis. There is an urgent need for elucidation of novel targets for TNBC therapy and to improve the prognosis of patients. The aim of this study was to evaluate the prognostic value of p62 expression in TNBC. METHODS AND RESULTS: Expression of p62 in tissue microarray was evaluated by immunohistochemistry in 163 patients with TNBC. The prognostic value of p62 expression was assessed by a Cox regression model adjusted for clinical characteristics. Overexpression of p62 was observed in 51 (31.3%) of 163 TNBC, and significantly correlated with advanced stage and a higher proportion of positive lymph nodes and lymphovascular invasion. A significant correlation was found between p62 expression and disease-free survival and overall survival. Accordingly, the 10-year distant metastasis-free survival for p62-overexpression and p62-underexpression patients were 58.9% and 92.5%, respectively (P<0.0001). Multivariate analysis indicated that p62-negative was a significant independent prognostic factor of disease-free survival (P=0.017), but not for overall survival (P=0.845) in all patients. CONCLUSION: Our results suggest that overexpression of p62 in TNBC is associated with a higher risk of distant metastases. This finding could open new avenues for the development of novel therapy strategies for TNBC.