MUC5AC and cancer: Many canonical mucins are associated with disease progression, especially MUC1, which is aberrantly expressed in ~60% of all cancers.63 Although more is known about MUC-1, MUC-24 is thought to be heavily sialylated with 24 predicted O-glycosites distributed across two mucin domains.64 Regardless, the O-glycosites which are occupied and the glycans decorating these sites for both MUC-1 and - 24 still remains to be elucidated.