https://www.selleckchem.com/products/eeyarestatin-i.html Background With the increasing use of immune checkpoint inhibitors, tumor mutation burden (TMB) assessment is now routinely included in reports generated from targeted sequencing with large gene panels; however, not all patients require comprehensive profiling with large panels. Our study aims to explore the feasibility of using a small 56-gene panel as a screening method for TMB prediction. Methods TMB from 406 non-small cell lung cancer (NSCLC) patients was estimated using a large 520-gene panel simulated with the prospective TMB status for the small panel. This information was then used to determine the optimal cut-off. An independent cohort of 30 NSCLC patients was sequenced with both panels to confirm the cut-off value. Results By comparing sensitivity, specificity, and positive predictive value (PPV), the cut-off was set up as 10 mutations/megabase, yielding 81.4% specificity, 83.6% sensitivity, and 62.4% PPV. Further validation with an independent cohort sequenced with both panels using the same cut-off achieved 95.7% sensitivity, 71.4% specificity and 91.7% PPV. The decreasing trend of sensitivity with the increasing trend of both specificity and PPV with a concomitant increase in the cut-off for the small panel suggests that TMB is overestimated but highly unlikely to yield false-positive results. Hence, patients with low TMB ( less then 10) can be reliably stratified from patients with high TMB (≥10). Conclusions The small panel, more cost-effective, can be used as a screening method to screen for patients with low TMB, while patients with TMB ≥10 are recommended for further validation with a larger panel. 2020 Translational Lung Cancer Research. All rights reserved.Background Sequencing artifacts, clonal hematopoietic mutations of indeterminate potential (CHIP) and tumor heterogeneity have been hypothesized to contribute to the low concordance between tissue and cell-free DNA (cfDNA) molecular profi