Targeting Mesenchymal-Epidermal Transition (MET) Aberrations in Non-Small Cell Lung Cancer: Current Challenges and Therapeutic Advances

The mesenchymal-epithelial transition (MET) receptor is a tyrosine kinase activated by its sole known ligand, hepatocyte growth factor (HGF). MET signaling regulates key cellular processes, including proliferation, survival, migration, motility, and angiogenesis. Dysregulation and hyperactivation of this pathway are implicated in multiple malignancies, including lung, breast, colorectal, and gastrointestinal cancers. In non-small cell lung cancer (NSCLC), aberrant activation of the <i>MET</i> proto-oncogene contributes to 1% of known oncogenic drivers and is associated with poor clinical outcomes. Several mechanisms can induce MET hyperactivation, including <i>MET</i> gene amplification, transcriptional upregulation of <i>MET</i> or <i>HGF</i>, <i>MET</i> fusion genes, and <i>MET</i> exon 14 skipping mutations. Furthermore, MET pathway activation represents a frequent mechanism of acquired resistance to EGFR- and ALK-targeted tyrosine kinase inhibitors (TKIs) in EGFR- and ALK-driven NSCLCs. Although MET has long been recognized as a promising therapeutic target in NSCLC, the clinical efficacy of MET-targeted therapies has historically lagged behind that of EGFR and ALK inhibitors. Encouragingly, several MET TKIs such as capmatinib, tepotinib, and savolitinib have been approved for the treatment of <i>MET</i> exon 14 skipping mutations. They have also demonstrated potential in overcoming MET-driven resistance to EGFR TKIs or ALK TKIs. On 14 May 2025, the U.S. Food and Drug Administration granted accelerated approval to telisotuzumab vedotin-tllv for adult patients with locally advanced or metastatic non-squamous NSCLC whose tumors exhibit high c-Met protein overexpression and who have already received prior systemic therapy. In this review, we summarize the structure and physiological role of the MET receptor, the molecular mechanisms underlying aberrant MET activation, its contribution to acquired resistance against targeted therapies, and emerging strategies for effectively targeting MET alterations in NSCLC.