RNA-sequencing to identify three different molecular grades and immune checkpoint cascades with distinct clinical behaviour in NMIBC.

412Background: NMIBC has a highly variable clinical behavior not adequately predicted by histological grade or clinical parameters. Some are indolent; others quickly progress to MIBC. Discrepancies between phenotype and genotype is compounded further by interobserver variability in pathological grading. There is an unmet need to improve the prediction of NMIBC. Methods: Whole transcriptomic analysis of 178 bladder tumors (158 NMIBC, 20 MIBC/metastatic) was performed from FFPE tissue incorporating messenger RNA expression, splice variants, gene fusion, mutation detection and immune checkpoint inhibitor cascades. CTLA, PD-1, LAG3, TIM3, TIGIT and B7 were compiled as an index including all major cascade genes. Data were integrated and tested for correlations with pathological grading and clinical outcomes. Conventional pathological grading for WHO 1973 (Grade 1, 2, 3) and 2004 (LG vs HG) classifications was reviewed by 3 expert uro-pathologists. Kappa statistic for interobserver variability was calculated. F...