C1GALT1C1 and colorectal carcinoma: To address this question, we used Tn‐expressing CRC cell lines (HCT116, SW480), which were previously generated through forced deletion of the key glycosyltransferase for O‐glycosylation T‐synthase,19, 20 to assess whether high levels of Tn antigen have an impact on Cosmc expression.