It was found that siRNA suppression of C1GalT markedly reduced the expression of Galβ1,3GalNAcα- (Core 1) and in the meantime increased the expressions of sialyl-GalNAcα- (sialyl-Tn), GalNAcα- (Tn) and GlcNAcβ1,3GalNAcα- (Core 3)-associated glycans in human colon cancer HT29 and SW620 cells. This evidence concerns the gene C1GALT1 and malignant colon neoplasm.