Beta 1 integrin predicts survival in breast cancer: a clinicopathological and immunohistochemical study

Background: The main focus of several studies concerned with cancer progression and metastasis is to analyze the mechanisms that allow cancer cells to interact and quickly adapt with their environment. Integrins, a family of transmembrane glycoproteins, play a major role in invasive and metastatic processes. Integrins are involved in cell adhesion in both cell-extracellular matrix and cell-cell interactions, and particularly, beta 1 integrin is involved in proliferation and differentiation of cells in the development of epithelial tissues. This work aimed to investigate the putative role of beta 1 integrin expression on survival and metastasis in patients with breast invasive ductal carcinoma (IDC). In addition, we compared the expression of beta 1 integrin in patients with ductal carcinoma in situ (DCIS). Methods: Through tissue microarray (TMA) slides containing 225 samples of IDC and 67 samples of DCIS, beta 1 integrin expression was related with several immunohistochemical markers and clinicopathologic features of prognostic significance. Results: beta 1 integrin was overexpressed in 32.8% of IDC. In IDC, beta 1 integrin was related with HER-2 (p = 0.019) and VEGF (p = 0.011) expression and it had a significant relationship with metastasis and death (p = 0.001 and p = 0.05, respectively). Kaplan-Meier survival analysis showed that the overexpression of this protein is very significant (p = 0.002) in specific survival (number of months between diagnosis and death caused by the disease). There were no correlation between IDC and DCIS (p = 0.559) regarding beta 1 integrin expression. Conclusions: Considering that the expression of beta 1 integrin in breast cancer remains controversial, specially its relation with survival of patients, our findings provide further evidence that beta 1 integrin can be a marker of poor prognosis in breast cancer.