Updated project metadata. Bladder carcinogenesis and tumour progression is accompanied by profound alterations in protein glycosylation. These include the presence of short chain O-glycans such as Tn and T antigens and their sialylated counterparts sialyl-Tn(STn) and sialyl-T(ST). The presence of such structures is commonly associated with poor prognosis. In search for prognosis biomarkers and novel therapeutic targets we have screened, using immunohistochemistry, a series of bladder tumours with differing clinicopathology for these short-chain O-glycans. Aiming at identifying protein targets, we have studied the O-glycoproteome of a pool of STn positive tumours from muscle invasive bladder cancer (MIBC) patients.