Interaction of MUC1 with EGFR in the nucleus of breast cancer cells promotes accumulation of chromatin-bound EGFR and co-localization of EGFR with phosphorylated RNA polymerase II.28 The present study shows that MUC1 expression increases EGF-induced EGFR activation in human breast and colon cancer cells. Here, MUC1 is linked to breast cancer.