Clinical and Genomic Features of <i>HER2</i> Exon 20 Insertion Mutations and Characterization of <i>HER2</i> Expression by Immunohistochemistry in East Asian Non–Small-Cell Lung Cancer

Abstract

The incidence of <i>HER2</i> mutations is 3.1% in East Asian nonsquamous NSCLC. <i>HER2</i> exon 20 insertion-mutated tumors appear genomically distinct from uncommon (nonexon 20 insertion) <i>HER2</i> mutations, the latter demonstrating higher TMB, co-occurring drivers, and predominant nonaging mutational signature. The therapeutic implications of the genomic and clinical features of <i>HER2</i>-mutated NSCLC warrant further investigation.