GCNT1 and cancer: In cancer cells, O-linked glycans are characterized to present immature and/or truncated structures due to reduced expression and/or activity of specific glycosyltransferases, such as beta 1,3-glalactosyltransferase [28] and core 2 beta-1,6-N-acetylglucosaminyltransferase (C2GNT), contributing to the accumulation of altered glycan structures such as Tn and sialyl-Tn antigens [29] and T-antigen and T-sialyl antigen [30].