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 stronnal 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 lumina! 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.