Mesothelin expression and survival outcomes in triple receptor negative breast cancer

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 (2P =.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 (2P =.43). Five-year overall survival was 85% and 91% in patients with mesothelin-positive and those with mesothelin-negative tumors (2P =.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.