Previous studies have shown that Tn antigen is an intermediate product in O-glycosylation of mucin and can be extended by the key enzyme T-synthase (core 1 β-1, 3-galactosyltransferase or C1β3Gal-T) through transfer galactose from UDP-galactose (uridine diphosphate galactose) to generate T antigen [core 1; Gal-β-(1→3)-GalNAc-α-O-Ser/Thr], found in several types of cancer [5]. Here, MUC5AC is linked to cancer.