A sample of the identified O-glycans of MUC-16 derived from UVPD analysis are summarized in Table , which groups the exact structures and compositions of each glycan identified based on linkages and glycosites, yielding comprehensive analysis of large glycoforms of MUC-16 not previously attained (full table is Table ). Glycoforms can be distinguished from one another down to the level of exact linkage patterns as exemplified by the differentiation of GalNAcGlcNAcGal(2)Neu5Ac(2) glycans for TLDRDSLYVNGF (Table , rows 2 and 3). The number of times each glycopeptide was identified was tallied to investigate whether specific core types were preferred over others at a given glycosite. Among the glycoforms identified, T[+1021.35]FLPPL showed preference for an elongated core 1 structure, with linkages αNeu5Ac2-6Gal1-4GlcNAc1-6Gal1-3GalNAc for this pentasaccharide. This glycan was identified at this glycosite eight times based on Byonic assignment and manual validation. The glycan identities themselves can demonstrate site preferences too. For example, the majority of glycans were localized at T14058 compared to other glycosites. While there is less ambiguity in characterization of smaller glycans, it is still critical to differentiate the linkages which might be crucial correlative biomarkers for disease states. For instance, for the doubly sialylated core 1 glycan, the αNeu5Ac2-6Gal linkage was identified nine times across five glycosites compared to seven times for the αNeu5Ac2-3Gal linkage. The significant diversity identified for the glycans underscores the need for comprehensive characterization, especially in the case of O-glycoproteomics.