132 Racial differences in TMB measures between paired tumor/normal and tumor-only sequencing across endometrial, bladder, and non-small cell lung cancers
Background Tumor mutational burden (TMB), defined as the number of somatic mutations per megabase of a tumor, is routinely used as a predictive biomarker for immunotherapy response in metastatic cancer patients. Sequencing of paired tumor and normal specimens allows for correction of TMB estimates with patient-specific germline variants. For tumor only assays, TMB estimates are corrected using germline variant annotations derived from population-scale germline variant surveys. These surveys often underrepresent minorities and individuals of non-European descent, leading to potential inaccuracies in TMB estimates in these populations. Methods Our cohort includes patients who underwent tumor genomic profiling with the Tempus xT Next Generation Sequencing (NGS) assay and diagnosed with non-small cell lung (NSCLC, n=4,583) endometrial (n=3,084), or urothelial (n=2,806) cancer. We used 654 ancestry informative markers selected to overlap the target regions of the 648-gene Tempus xT NGS assa
