MUC1 and neoplasm: This consequently results in increased homotypic aggregation and heterotypic adhesion of circulating tumour cells to the blood vascular endothelium and tumour cell spread.19,20 Thus, overexpression of MUC1 in epithelial cancer cells can influence several steps in tumourigenesis and metastasis and each of these is influenced not only by the MUC1 protein expression but also by the MUC1 localization/depolarization, its glycosylation patterns and the presence of its interacting proteins in the tumour microenvironment.