EGFR and non-small cell lung carcinoma: EGFR Mutations in Non-Small Cell Lung Cancer (NSCLC): Specific mutations in the epidermal growth factor receptor (EGFR) gene in NSCLC, such as EGFR exon 19 deletions or the L858R mutation, are predictive biomarkers for response to EGFR tyrosine kinase inhibitors (TKIs) like gefitinib, erlotinib, and osimertinib [403].