Cancer-associated CA125 antigen presents both N- and O-glycosylation, with N-linked glycans being mainly composed of bi-antennary complex-type and high mannose-type oligosaccharide chains, and O-glycans are, predominantly, mono- and disialylated core type 1 (Galβ1,3-GalNAc) and core type 2 glycans [Galβ1,3-(GlcNAcβ1,6)-GalNAc]. The gene discussed is MUC16; the disease is cancer.