One such scenario is the treatment of metastatic NSCLC with exon 19 deletions or L858R mutations in EGFR. Here, SOC therapy includes the tyrosine kinase (TKI) inhibitor erlotinib (EGFR inhibitor), to which resistance invariably develops, approximately half of which occurs through the acquisition of an additional T790M mutation in EGFR. A second generation EGFR inhibitor—osimertinib—is, however, effective in patients with EGFR T970M erlotinib-resistance mutations. Here, EGFR is linked to non-small cell lung carcinoma.