Impact of Age on Tumor Mutation Burden in Gastric patients:a secondary analysis based on a cross-sectional study

Abstract

Background Gastric carcinoma is aggressive cancer with a poor prognosis. Recent years, immunotherapy has been validated effective in a proportion of patients. Tumor mutational burden (TMB),microsatellite instability (MSI) status and programmed cell death-ligand 1 (PD-L1) expression are potential biomarkers to predict efficacy to immunocheckpoint inhibitors (ICIs). This study was undertaken to explore the correlationship between these biomarkers using the published data in a large patient cohort of gastrointestinal cancers. Method In total,367 gastric cancer patients were examined in this study. MSI and TMB were assessed by next-generation sequencing (NGS). PD-L1 expression was determined by immunohistochemistry. Results The population was divided into four groups according to age,TMB-High and MSI-high participants were more frequent in older groups.After adjusting sex, differentiation,histology,specimensite,MSI status and PD-L1 expression, a non-linear relationship between age and TMB was found,which had an inflection point of 73 years.The effect sizes and the confidence intervals on the left and right sides of the inflection point were 0.06 (-0.01to 0.13) and 0.56 (0.33 to 0.79), respectively. In different subgroups analysis,similar trends were observed. Conclusion The relationship between age and TMB is non-linear. Age was positively correlated with TMB when age was more than 73 years.