ST3GAL1 and urinary bladder carcinoma: One hypothesis to explain this discrepancy between ST3Gal.I expression and PNA reactivity is the fact that, in bladder cancer tissue, the ST3Gal.I is acting specifically on a limited number of molecules and any resulting increased content of sialyl-T containing glycans, due to its activity, is not perceptible by the adopted methodology, the dot blot analysis.