MGL binds to terminal α-or β-GalNAc residues in a calcium-dependent manner1−3 and can employ a secondary binding site outside the carbohydraterecognition domain (CRD) to engage with glycoproteins4 or disaccharides.5 MGL was reportedto recognize Tn-modified Mucin 1 (Tn-MUC1) tandem repeat (TR) glycopeptides6,7 on several cancer cell lines, including colon, lung, and bronchioalveolarcarcinoma.8 The MUC1 glycoprotein is amembrane-bound mucin found on epithelial cells, but aberrantly expressedwith truncated glycans in several cancer cell lines.9−12. The gene discussed is MUC5AC; the disease is cancer.