Relationship between survival outcomes and microsatellite instability, tumor infiltrating lymphocytes and programmed cell death ligand-1 expression in patients with bladder cancer and radical cystectomy.

Abstract

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.