Association between transforming growth factor-β1 expression and the clinical features of triple negative breast cancer.

The aim of the present study was to investigate the association between the expression levels of transforming growth factor-β1 (TGF-β1) and the clinical pathological characteristics and prognosis of triple negative breast cancer (TNBC) through study of TNBC patient tissue samples. The biological effects of TGF-β1 on TNBC cells and the potential signal transduction pathway are additoinally investigated. Immunohistochemistry was utilized to investigate expression changes of the positive rate of TGF-β1 in the TNBC, compared with the non-TNBC group, to explain the association between TGF-β1 and clinical pathological characteristics and prognosis. MDA-MB-231 cells were treated with TGF-β1 and subsequently the invasion and migration abilities, and the expression of proteins in certain signaling pathways were assessed before and after the treatment. Positive expression of TGF-β1 was observed in 52.5% of TNBC tissue samples, which was higher than that observed in non-TNBC group (27.5%). High levels of TGF-β1 expression were not significantly associated age, menopausal status, family history of cancer or tumor size; however, tumor histological grade and axillary lymph node metastasis were significantly associated (P<0.05). In addition, when the TGF-β1 expression levels are higher, the 5-year disease-free survival rate is lower. TGF-β1 expression promoted the invasion and migration of MDA-MB-231 cells, and the expression of Smad2 protein and P38 protein was increased, indicating that Smad2 protein and the P38 signaling pathway may serve an important role in TNBC.