Overexpression of caveolin-1 in cancer-associated fibroblasts predicts good outcome in breast cancer.

BACKGROUND The aim of this study was to investigate the expression of caveolin-1 (Cav-1) in cancer-associated fibroblasts (CAFs) and to explore its correlation with clinicopathologic parameters and prognosis. MATERIALS AND METHODS Cav-1 expression was detected in the stroma of 143 patients with breast cancer, 10 patients with ductal carcinoma in situ (DCIS), and 10 normal breast tissue samples. RESULTS Overexpression of stromal Cav-1 in breast cancer was associated with histological type, low histological grade, estrogen receptor (ER) negativity, and molecular subtypes. The expression rate of stromal Cav-1 in breast cancer (65.7%, 94/143) was significantly higher than that of DCIS (0%, 0/10) and normal breast tissue (0%, 0/10) (p = 0.000). A positive correlation was found between stromal Cav-1 and ER (p = 0.046, rs = 0.218). Stromal Cav-1 expression in luminal B was significantly higher than in basal-like type (p = 0.048). Furthermore, stromal expression of Cav-1 was significantly correlated with the 5-year survival rate (p = 0.029), and it was an independent prognostic factor (p = 0.009). CONCLUSION Cav-1 expression in CAFs was correlated with histological type, histological grade, ER status, and molecular subtypes in breast cancer. Stromal Cav-1 expression was an independent prognostic factor, and the absence or reduction of Cav-1 expression in stromal CAFs of invasive breast cancer predicts poor prognostic outcome.