The Sda blood group carbohydrate structure, GalNAcβ1,4(NeuAcα2,3)Galβ1,4GlcNAc-R, and β1,4-GalNAc transferase (β1,4-GalNAcT) II, which is responsible for Sda synthesis gene expression, are abundantly expressed in the normal gastrointestinal mucosa, while their expression levels are markedly decreased in gastric and colonic cancers. The gene discussed is B4GALNT2; the disease is malignant colon neoplasm.