The well-described crucial role of EGFR in the advancement of breast cancer prompted us to investigate the effects of EGFR inhibition in TNBC cells with different ERβ status (MDA-MB-231 (ERβ-positive) and shERβ MDA-MB-231 (ERβ-suppressed)) in the expression of matrix molecules implicated in breast cancer progression, such as MMP2, -9, -7 and -14 (MT1-MMP). The gene discussed is ESR2; the disease is breast cancer.