MUC1 and breast cancer: For example MUC1, a mucin-like protein on the apical membrane of epithelia, is associated with metastasis.51 In hamster ovary cells palmitoylation plays a role in modulating MUC1 recycling from endosomes to the plasma membrane,52 and intracellular localization of MUC1 is altered in a breast cancer subtype-specific manner during tumorigenesis.53