High Expression Level of α6 Integrin in Human Breast Carcinoma Is Correlated with Reduced Survival

Abstract

We recently reported that α6 integrin mediates experimental metastasis in mice by functioning in the adhesion of tumor cells to the vascular endothelium. In the current study, we investigated the expression of human α6 integrin in invasive breast carcinomas of 119 women. In 50% of the tumors α6 integrin was expressed in the majority of the cells, and this expression was correlated with reduced survival time. By contrast, the 24% of patients with breast tumors devoid of α6 integrin expression all survived. The tumors were also evaluated for clinical risk factors including histological grading and steroid receptor level. The combination of these factors with α6 integrin expression was superior in predicting overall survival than considering the other factors alone. The correlation with decreased survival time was consistent, regardless of whether the tumors expressed the α6 integrin A or B forms, which differ in their cytoplasmic domain. On the basis of this pilot study we consider α6 integrin expression to be a novel prognostic marker for human breast cancer.