HIGH EXPRESSION LEVEL OF ALPHA-6 INTEGRIN IN HUMAN BREAST-CARCINOMA IS CORRELATED WITH REDUCED SURVIVAL

We recently reported that alpha 6 integrin mediates experimental metas tasis in mice by functioning in the adhesion of tumor cells to the vas cular endothelium. In the current study, we investigated the expressio n of human alpha 6 integrin in invasive breast carcinomas of 119 women . In 50% of the tumors alpha 6 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 a lpha 6 integrin expression all survived. The tumors were also evaluate d for clinical risk factors including histological grading and steroid receptor level. The combination of these factors with alpha 6 integri n expression was superior in predicting overall survival than consider ing the other factors alone. The correlation with decreased survival t ime was consistent, regardless of whether the tumors expressed the alp ha 6 integrin A or B forms, which differ in their cytoplasmic domain. On the basis of this pilot study we consider alpha 6 integrin expressi on to be a novel prognostic marker for human breast cancer.