MUC6 and colorectal carcinoma: Aberrant expression of MUC4 during CRC progression has also been reported, and overexpression of MUC4 has been suggested to predict poor survival among patients with early stage (stage I and II) tumors but not in patients with advanced-stage (stage III and IV) tumors [19, 22], Also MUC6 has been suggested to be involved in CRC development [20, 23].