Mesothelin expression and survival outcomes in triple receptor negative breast cancer.

Abstract Background Mesothelin is an ideal tumor-associated marker for the development of targeted therapy due to its limited expression in normal tissues. The aim of this study was to evaluate mesothelin expression in triple-negative breast cancer (TNBC) and its correlation with survival outcomes. Methods Mesothelin expression was completed by using immunohistochemistry and was quantified by the H score. An H score > 10 was considered positive. Patient characteristics were compared by mesothelin expression. The Kaplan-Meier product limit method was used to estimate survival outcomes. Cox proportional hazards models was used to adjust for patient and tumor characteristics. Results The median age was 52 years. Of the 109 patients with TNBC, 37 (34%) were positive for mesothelin expression. There were no differences on patient and/or tumor characteristics by mesothelin expression with the exception of high frequency of lymphovascular space invasion in mesothelin-negative tumors (2 P  = .03). At a median follow-up of 75.8 months, 20 (18.3%) patients had experienced a recurrence, and 22 (20.2%) had died. Five-year progression-free survival was 87% and 92% in patients with mesothelin-positive and those with mesothelin-negative tumors (2 P  = .43). Five-year overall survival was 85% and 91% in patients with mesothelin-positive and those with mesothelin-negative tumors (2 P  = .57), respectively. Mesothelin expression was not an independent predictor of survival outcomes. Conclusion Mesothelin expression was identified in 34% of patients with TNBC. Mesothelin expression did not correlate with survival outcomes in patients with TNBC.