T and sialyl-T antigens are expressed in bladder tumor tissue and urothelium. Tumor (T) and Urothelium (U) samples from patients were analyzed by dot blot staining with PNA, which binds to T-antigen. Samples were arranged by tumor type, namely, nonmuscle-invasive without (IA) and with recurrence (IB) and muscle-invasive (II) bladder cancer and non-malignant tumors (III) and by treatment with neuraminidase (N) or mock treated (M). PNA binds to non neuraminidase treated samples, of all patients' groups, indicating the presence of T-antigens. In the majority of the samples, PNA binding is strongly increased after neuraminidase treatment.