Major targets for mutation in lung cancer include EGFR mutations, ALK rearrangements, ROS1 rearrangements, RET rearrangements, neurotrophic tyrosine receptor kinase (NTRK) fusions, mesenchymal–epithelial transition factor (MET) exon 14 skipping mutation, KRAS G12C mutation, BRAF V600E mutation, and ERBB2 (HER2) mutation. The gene discussed is ERBB2; the disease is lung carcinoma.