High expression of glycoprotein non-metastatic melanoma protein B is associated with resistance to neoadjuvant chemotherapy in triple-negative breast cancer.

AIMS: This retrospective single-center study aimed to investigate the expression of glycoprotein non-metastatic melanoma protein B (GPNMB) and its association with clinicopathological parameters, Miller-Payer (MP) grading, neoadjuvant chemotherapy (NAC), and prognosis in triple-negative breast cancer (TNBC). METHODS: . RESULTS: Positive expression of GPNMB was significantly associated with low MP grade and poor prognosis of patients with TNBC. Knockdown of GPNMB suppressed proliferation and migration, promoted apoptosis, and enhanced chemosensitivity in TNBC cells. CONCLUSIONS: These results indicate that GPNMB expression can serve as a potential biomarker for predicting the pathological response to NAC (in addition to MP grading) and as a prognostic marker for TNBC. The important limitation of this study is the small number of patients; further validation is needed.