The basal subtype of breast carcinomas may represent the group of breast tumors that could benefit from EGFR-targeted therapies

The recent understanding of the molecular basis of breast cancer growth and progression led to the identification of tumor subtypes with potentially different biologic behavior. In addition, targeted therapies are increasingly successful in cancer treatment. We recently reported that most of the ER-negative/PR-negative/HER2-negative patients, a group that presents a therapeutic challenge for the oncologist, express EGFR. We now report that the majority of these patients express cytokeratin CK5/6 and therefore belong to the basal subtype of breast carcinomas. These basal subtype lesions are usually high-grade tumors of ductal histology with a high proliferation rate. We propose that the majority of the "triple negative" patients have basal subtype tumors with high EGFR expression and that these tumors may be the subgroup of breast carcinomas that could potentially benefit the most from novel EGFR-targeted therapeutic strategies.