Correlation between K-RAS mutant subsets, TP53 mutation, and PD-L1 status in non-small cell lung cancer (NSCLC).

Abstract

e14272 Background: K-RAS is a non-targetable mutation with no established predictive value. However, PD-L1 is the only approved predictive marker for immunotherapy in NSCLC. K-RAS mutation like PD-L1 has been associated with smoking. TP53 and K-RAS mutations have been identified in aggressive neoplasms. We hypothesized that K-RAS mutant NSCLC has higher PD-L1 expression suggestive of improved response to immunotherapy. Methods: The Caris database from 2016 - 2018 was queried and patients with NSCLC were identified. ≥1% staining for PD-L1 (22c3 antibody) was considered positive. PD-L1 expression as well as K-RAS and TP53 mutation status were analyzed and correlation between different variables were identified using ANOVA. Results: We identified 8,471 patients with NSCLC, where 66% had TP53 mutation and 26.9% had K-RAS mutation; both mutations were identified in 12% of the patients. In the subset of combined K-RAS and TP53 mutations there were 71.48% having positive PD-L1 expression with female predominance 1.4:1. Of the eight main K-RAS mutation subsets, G12C subset was the most common. Compared to other K-RAS subtypes, G12C was associated with the higher occurrence of PD-L1 positivity (62.68%,p < 0.04; Table). Conclusions: In comparison to other subsets of K-RAS mutation, G12C had the highest occurrence of PD-L1 expression, suggestive of improved response to immunotherapy. However, the subset of patients with combined K-RAS and TP53 mutations had a higher occurrence for the PD-L1 positive status of 71.48%. [Table: see text]