MUC1 and cancer: It is important to note that SN-131 does not bind to MUC1 TRD when the threonine residue of this immunodominant region is modified with STn, dST, or core 2-type mature complex O-glycan structures (Fig. 2a).19 We considered that SN-131 is a highly potential anti-MUC1 antibody because this antibody binds specifically MUC1 TRD having core 1 type O-glycans overexpressed in many cancers including pancreatic cancer but not core 2 type O-glycans found in normal cells.