For NSCLC driven by ALK, ROS1, or RET fusions or by less common mutations (MET exon 14 skipping, BRAF V600E, HER2- Human Epidermal Growth Factor Receptor 2- exon20 insertions, etc.), co-occurring alterations also play a role, though data are somewhat less extensive than for EGFR or KRAS. The gene discussed is ERBB2; the disease is non-small cell lung carcinoma.