[The expression of fibroblast activation protein-α in primary breast cancer is associated with poor prognosis]

To evaluate the prognostic value of fibroblast activation protein-α (FAP-α) expression in primary lesions of breast cancer patients and the relationship with the clinicopathologic features.

Paraffin sections and clinical data were retrospectively collected from 130 stage I-III breast cancer patients who had underwent surgery at the Chinese PLA General Hospital from January 1st, 2000 to December 31st, 2002. Immunohistochemistry was used to assess FAP-α expression in primary lesions of breast cancer to evaluate the associations of FAP-α expression with transforming growth factor-β1 (TGF-β1) expression in breast cancer and patients' clinicopathologic characteristics and prognosis.

FAP-α was seen in cytoplasm of tumor cells and interstitial fibroblasts. Density of interstitial FAP-α-positive fibroblasts was positively correlated with the staining density of interstitial TGF-β-positive cells. Intensity of CTLA-4 expression in tumor cells was positively correlated with TGF-β1 expression in tumor cells. In patients whose lesions were negative for both estrogen and progesterone receptors, density of interstitial FAP-α-positive fibroblasts was an independent adverse prognostic factor for disease-free survival (DFS) and overall survival (OS); intensity of CTLA-4 expression in tumor cells was an independent adverse prognostic factor for DFS and OS.

High expression of FAP-α in primary breast tumors is associated with a bad prognosis in patients whose lesions are negative for both estrogen and progesterone receptors. Expression of TGF-β1 is positively related with FAP-α expression in primary breast tumors.