Increased pSmad2 expression and cytoplasmic predominant presence of TGF-βRII in breast cancer tissue are associated with poor prognosis: results from the Shanghai Breast Cancer Study.

Abstract

Perturbations of transforming growth factor-beta (TGF-β) signaling are pivotal to tumorigenesis and tumor progression through their effects on cell proliferation and cell invasion. This study aims to evaluate the association of TGF-βRII and pSmad2 protein expressions in breast tissue with clinicopathological factors and prognosis of breast cancer. Expression of the TGF-βRII and pSmad2 proteins was assessed in breast tissue of 1,045 breast cancer cases in the Shanghai Breast Cancer Study using a double immunofluorescence staining method, which was validated with standard single immunostains. TGF-βRII expression intensity was positively associated with younger age at diagnosis (P = 0.03), pre-menopausal status (P = 0.03), and lower TNM stage (P = 0.04). Cytoplasmic predominant expression pattern of TGF-βRII was associated with older age at diagnosis (P = 0.04) and invasive histological type (P = 0.03). Increased pSmad2 expression was associated with higher breast cancer grade (P < 0.01). Higher pSmad2 expression [HR (95 % CI):1.48 (1.07-2.04), P = 0.02] and cytoplasmic predominant TGF-βRII expression [HR (95 % CI): 1.80 (1.08-3.00), P = 0.02] were significantly associated with reduced cancer-free survival. Our data suggest that TGF-βRII and pSmad2 expressions are associated with certain clinical and pathologic features of breast cancer. A cytoplasmic predominant TGF-βRII expression pattern and a higher pSmad2 expression were associated with decreased breast cancer survival. Our study provides additional evidence to support the important role of TGF-β signaling in breast cancer prognosis.