Prognostic difference of molecular subtypes in non-muscle invasive bladder cancer

In recent years, 2 molecular types have been defined in urothelial carcinoma, as luminal and basal. The molecular subtyping is generally based on genetic studies in non-muscle invasive bladder cancer (NMIBC) however the studies with immunohistochemical reflection of this subtyping in NMIBC is limited. In our study, we aimed to use GATA3 and keratin 5/6 for subtyping of NMIBC, and to investigate the follow-up results. Materials and methods: Patients who underwent transurethral resection for the first time and whose final diagnosis was reported as NMIBC were prospectively included. A block representing the tumor was stained with GATA3 and keratin 5/6.The relationships between the subtypes and demographic data, recurrence rates, and time to recurrence were evaluated. A total of 100 patients diagnosed with NMIBC were included. The keratin 5/6 negativity was 64% and all of these patients were GATA3 positive. The keratin 5/6 positivity was 36%. None of the age, tumor size, lamina propria invasion, keratin 5/6 and GATA3 positivity were significant for predicting the risk of recurrence. The mean time to recurrence was 283 days and 332 days in the keratin 5/6 positive and negative group, respectively but the relation was not statistically significant. Molecular classification is difficult due to technical reasons, but it can be performed with GATA3 and keratin 5/6 by immunohistochemistry. New studies are needed to determine the clinical differences and to specialize the management of bladder tumors.