Status ofPD-1 and PD-L1 expression in invasive urothelial carcinoma ofthebladder with mismatch repair protein deficiency.

Abstract

It has been reported that mismatch repair deficient (d-MMR) tumors show sensitivity to immune checkpoint inhibitors. We aimed to evaluate thecorrelation ofd-MMR and PD-1/PD-L1 expression in invasive urothelial carcinoma ofthebladder. Tissue microarray (TMA) tissues were stained PD-1/PD-L1 and MMR proteins. Theexpression ratio ofthese markers has been compared with histopathologic parameters. d-MMR tumors were more superficial muscle invasive (p=0.012). When thed-MMR, and PD-1/PD-L1 expression ratios were examined, asignificant correlation was obtained between thed-MMR and PD-L1 expression ratio of> 5% in both thetumor and immune cells (p=0.02 and p=0.004, respectively). Theexpression ratio was higher in thepatients without MMR loss. PD-1 and PD-L1expression in those with MSH6 loss was one or none. When PD1/PDL1 expression was compared with histopathological parameters, asignificant relationship was observed between tumor grade and depth ofmuscle invasion. PD-L1 expression was not observed in thesuperficial muscle invasive tumors. This study was shown thestatus ofd-MMR and PD-1/PD-L1 in invasive urothelial cancers and their correlation with prognostic markers. PD-1/PD-L1 expression may contribute to theprogression and poor prognosis ofbladder cancer. However, further studies are required to research theclinical utility.