PURPOSE

Platin-based chemotherapies are first-line treatment methods after surgery in bladder cancer. Recently, novel immunotherapies emerged after platin-based regimens. The purpose of this study was to evaluate the prognostic significance of microsatellite instability (MSI), tumor infiltrating lymphocytes (TILs) and programmed cell death ligand-1 (PD-L1) expression which are used as predictive biomarkers in immunotherapy.

METHODS

Clinical and pathological features of bladder cancer patients who underwent radical cystectomy were retrospectively analyzed from their records in this single-center study. PD-L1, PD-L1 on TIL, PMS2, MSH2, MSH6 and MLH1 immunohistochemistry staining were carried out to archieve resected tumor specimens of the eligible patients. MSI was evaluated according to existing of PMS2, MSH2, MSH6 and MLH1.

RESULTS

MSI was high in 24.6% of 61 patients. PD-L1 expression on tumor cells and PD-L1 expression on TIL were positive in 14.8% and 16.4% of the patients, respectively. Intratumoral TIL rate was >10% in 12 patients (19.7%). There was no statistically significant relationship between PD-L1, PD-L1 on TIL, MSI and TIL rate and patients' characteristics including sex, stage, pathologic grade and lymph node status. There was a positive trend between MSI-high patients and overall survival (OS) (p=0.089). Univariate analysis did not reveal any significant difference at 3-years OS with PD-L1 tumor expression and PD-L1 expression on TIL and TIL rate >10% (p=0.822, p=0.638, p=0.318, respectively) Conclusion: This study revealed that there is a positive trend between OS and MSI but no prognostic significance of PD-L1 and TIL which are proven predictive biomarkers of immunotherapy in patients with bladder cancer.