The Prognosis of Mutation Subtypes of KRAS Gene and Their Relation with the Expression Level of PD-L1 in Advanced Lung Adenocarcinoma

Objective This study aims to explore the prognostic role of mutation subtypes of Kirsten rat sarcoma viral oncogene （KRAS） in advanced lung adenocarcinoma and their relation with expression level of programmed death ligand 1 （PD-L1）. Methods We retrospectively collected tumor specimens of 91 advanced KRAS-mutant lung adenocarcinoma. Next-generation sequencing was employed to detect the genomic alterations of cancer related genes and immunohistochemistry was applied to determine the expression level of PD-L1. Clinical and survival data were collected for Kaplan-Meier analysis. Result KRAS G12C, G12D, G12V and other mutations made up 33.0%, 20.9%, 15.4% and 30.8% of all patients respectively. Positivity of expression of PD-L1 ≥1% were 86.7%, 44.4% and 50.0% respectively in KRAS G12C, G12D and G12V subgroups. Positive ratio of PD-L1 ≥1% in KRAS G12C is higher than KRAS G12D tumors （P=0.028）. Conclusion Mutation subtypes of KRAS were not prognostic of survival in KRAS mutant patients with NSCLC. Yet expression of PD-L1 was higher in KRAS G12C versus other mutation subtypes, which needs further investigation for its potential predictive role for immune therapy.