EGFR variant profiles in lung adenocarcinoma from different regions of Brazil: a multi-institutional study using a rapid RT‒PCR platform

Abstract Background Lung adenocarcinoma frequently harbors activating EGFR variants, but their distribution may vary across Brazil due to regional demographic and ancestral differences. This study evaluated the frequency and subtype distribution of EGFR variants in three Brazilian regions and examined associations with clinicopathological features. Methods A retrospective electronic search was performed to select patients with lung adenocarcinoma who underwent EGFR testing using a rapid RT–PCR platform across southeastern (SE), southern (S), and northeastern (NE) Brazil. Results EGFR variants were identified in 21% of all patients. Female patients had a higher frequency than males (p < 0.01), and the frequency varied significantly by region: 32% in the NE, 27% in the SE, and 11% in the S. The most common alterations were exon 19 deletion (45%) and p.Leu858Arg (43%). Variant subtype distribution also differed by region: the NE showed a disproportionately high frequency of exon 19 deletion, whereas the SE was the only region with p.Gly719Ala/Cys/Ser variants. Regional differences remained significant even after adjusting for gender (p < 0.01). Conclusion EGFR variant frequency and subtype distribution vary markedly across Brazilian regions, with the NE showing the highest overall mutation rate and the S the lowest. These patterns likely reflect underlying demographic, ancestral, and environmental differences and highlight the importance of regional molecular profiling to inform targeted therapy strategies and optimize resource allocation.