Abstract
Lung cancer leads cancer-related mortality worldwide. Non-small-cell lung cancer
(NSCLC), the most prevalent subtype of this recalcitrant cancer, is usually diagnosed
at advanced stages, and available systemic therapies are mostly palliative. The
probing of the NSCLC kinome has identified numerous nonoverlapping driver genomic
events, including epidermal growth factor receptor (EGFR) gene
mutations. This review provides a synopsis of preclinical and clinical data on
EGFR mutated NSCLC and EGFR tyrosine kinase
inhibitors (TKIs). Classic somatic EGFR kinase domain mutations
(such as L858R and exon 19 deletions) make tumors addicted to their signaling
cascades and generate a therapeutic window for the use of ATP-mimetic EGFR TKIs. The
latter inhibit these kinases and their downstream effectors, and induce apoptosis in
preclinical models. The aforementioned EGFR mutations are stout
predictors of response and augmentation of progression-free survival when gefitinib,
erlotinib, and afatinib are used for patients with advanced NSCLC. The benefits
associated with these EGFR TKIs are limited by the mechanisms of tumor resistance,
such as the gatekeeper EGFR-T790M mutation, and bypass activation of signaling
cascades. Ongoing preclinical efforts for treating resistance have started to
translate into patient care (including clinical trials of the covalent EGFR-T790M
TKIs AZD9291 and CO-1686) and hold promise to further boost the median survival of
patients with EGFR mutated NSCLC.
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