Epidermal growth factor receptor (EGFR) exon 20 (EGFR exon 20)

The Epidermal Growth Factor Receptor (EGFR) exon 20 insertion mutation is a specific oncogenic driver primarily found in non-small cell lung cancer (NSCLC), representing approximately 1-10% of all EGFR mutations [1.1.3, 1.2.1]. These mutations involve in-frame insertions or duplications within the kinase domain, which stabilize the receptor in an active conformation and lead to constitutive signaling through pathways like PI3K/AKT and MAPK [1.1.4, 1.3.3]. Unlike classical EGFR mutations, exon 20 insertions create a restricted drug-binding pocket that confers intrinsic resistance to most first- and second-generation tyrosine kinase inhibitors (TKIs) [1.1.5, 1.3.2]. Therapeutic approaches have shifted toward specialized agents such as the bispecific antibody amivantamab, which targets both EGFR and MET, and novel TKIs like sunvozertinib and mobocertinib [1.2.1, 1.2.3]. Clinical identification of these variants typically requires next-generation sequencing (NGS) due to the limitations of standard PCR-based assays [1.4.1]. Major safety concerns include toxicities arising from the inhibition of wild-type EGFR, such as severe diarrhea and skin rash, as well as the development of secondary resistance mutations [1.3.1, 1.4.2]. Despite the approval of targeted therapies, managing the narrow therapeutic window between mutant and wild-type EGFR remains a significant challenge in clinical practice [1.2.3, 1.3.1].

Other names

EGFR exon 20 insertionEGFR Ex20InsERBB1 exon 20HER1 exon 20Epidermal growth factor receptor exon 20 insertion mutation

Inhibition of the mutated EGFR tyrosine kinase domain through small molecule binding or antibody-mediated blockade of receptor signaling and degradation.