Decoding EGFR Exon 20 Insertions: Guiding Therapy Beyond One-Size-Fits-All

EGFR exon 20 insertion (ex20ins) mutations represent a distinct subset of NSCLC, accounting for approximately 2% to 10% of EGFR-mutant population.1 Unlike the common sensitizing mutations exon 19 deletions and L858R, ex20ins are characterized by extreme molecular heterogeneity spanning a wide range of insertion sizes, sequence compositions, and structural locations.1 This structural diversity not only confers intrinsic resistance to conventional tyrosine kinase inhibitors (TKIs) but also creates potential variability in drug sensitivity among the different variants.