Introduction

There has been a growing interest in urothelial bladder cancer, probably due to new treatment modalities that will require molecular phenotyping. In order to tackle this issue, the aim of this study is to identify cases of HG-NMIBC at higher risk, by using the recently developed molecular classification of HG urotelian tumours: basal and luminal type.

Methods

We retrospectively analyzed data from 70 patients with primary or recurrent T1G3 NMIBC. All patients underwent complete transurethral resection of the bladder tumor including muscle in the sample. Every case received BCG induction. The study protocol (cod 2015/072) received approval from the ethics committee of clinical investigation of Galicia (Spain). Written informed consent was gained from all alive patients. Pathology specimens were reviewed by two independent investigators. Immunohistochemistry with prediluted antibodies against CD44 (Clone SP37), CK20 (Clone SP33), all of them from Ventana, and a concentrated antibody antiCK5 (Clone XM26, Novocasta) were used for categorized NMIBC as Luminal (CK5 and CD44 negative, CK20 positive) and Basal (CK5, CD44 positive and CK20 negative). Data were analyzed using SPSS version 19.0 for Windows IBM, Chicago, USA. A p value <0.05 was considered statistically significant.

Results

76 % of cases (51/67) were categorized as Luminal and 3% (2/67) as Basal. Only 20.9% of cases (14/67) were not classifiable due to inconclusive test. Recurrence rate was lower in Luminal group (33%), compared with the basal group (50%). This differences do not reach statistical significance. Progression rate was lower in Luminal group (12%) compared with Basal group (50%), without statistical significance

Conclusions

Immunohistochemistry is useful for molecular classification of HR-NMIBC in luminal and basal types. In our study, most of HG-NMIBC belonged to the luminal type group. Given that cases in the basal group has presented a worse clinical outcome, and due to the availability of targeted treatment already used for other tumors, larger studies are needed to elucidate the role of this markers in the follow up and treatment for HG-NMIBC tumors.

Funding

none