So far, no definite mechanism has been established to understand the elevated intracellular presence of MUC in cancer, but different postulations, specifically for MUC1, have been put forth including; its impaired recycling, altered glycosylation, altered endocytosis and other presumed changes in MUC dynamics (Fig. 2), which will be discussed in detail in the next sections. The gene discussed is MUC1; the disease is cancer.