Given that the cytoplasmic tail of MUC16 can associate with the actin cytoskeleton via its ERM-binding domain [13] and that MUC1 has been shown in breast cancer cells to mediate actin cytoskeletal membrane protrusive motility by way of ICAM-1 ligation and an Src signaling cascade [39], we hypothesized that MUC1 and MUC16 may, through cytoskeleton association, induce membrane folds or projections on the epithelial cells’ apical surface. The gene discussed is MUC1; the disease is breast cancer.