Genomic Landscape of Non-Squamous Non-Small Cell Lung Cancer in a Southern Brazilian Population: High PDL-1 Expression and Enrichment of EGFR and TP53 Mutations.

Non-small cell lung cancer (NSCLC) is one of the leading causes of cancer-related deaths worldwide. The genomic database for NSCLC is expanding rapidly, highlighting the importance of characterizing subpopulations from diverse regions. This study aims to identify and correlate genomic variants in patients with non-squamous NSCLC from two cities in Paraná, Brazil, and compare these findings with data from The Cancer Genome Atlas (TCGA) and the broader Brazilian population. We conducted a retrospective study sequencing tumor sample from 133 patients. An in silico analysis was performed for gene functional analysis. Additional data on tumor mutational burden (TMB), microsatellite status, and clinicopathological characteristics were also collected. The mutational load in the studied population was comparable to that of the TCGA cohort. However, gene expression profiles differed significantly, particularly for the EGFR, TP53, KRAS-NRAS, STK11-KEAP1, MTAP-CDKN2A/B, and PDL-1 genes. The gene expression profile in this study also showed marked differences from the general Brazilian population, with notably higher expression rates of EGFR and PDL-1. Specifically, considering the PDL-1 expression levels, 14% were classified as hyper-expressors, 33% as hypo-expressors, and 52% as non-expressors. These proportions were statistically distinct from global literature but aligned with the Brazilian profile. The genomic profile of patients with NSCLC in Paraná reveals a regional signature, characterized by a higher frequency of EGFR and TP53 mutations, along with elevated PDL-1 expression. These findings highlight the potential for regional variations in NSCLC, which could inform personalized treatment strategies for this population.