The O-glycosylation of the core 3 structure is essential for the differentiation of gastrointestinal tract cup cells and the formation of the mucosal barrier.Regulation of core 3 structure expression by C1GALT1 may affect the development of colorectal cancer, and its overexpression may reduce the core 3 structure, which can induce cancer. The gene discussed is C1GALT1; the disease is colorectal cancer.