MUC1 and breast cancer: In another study, the degree of GalNac O-glycosylation of the trans-membrane protein MUC1 determined the rate of its endocytosis in chinese hamster ovary cells, with higher rates of endocytosis and degradation experienced by the under-glycosylated form (Altschuler et al., 2000) and O-glycan remodelling of MUC1 in the recycling endosome of human epithelial kidney cells and breast cancer cells was suggested to control its subsequent fate (Razawi et al., 2013).