ERBB2 and non-small cell lung carcinoma: Despite her relatively young age and the lack of risk factors such as smoking, additional research showed a stage IV human epidermal growth factor receptor 2 (HER2) exon 20 insertion non-small cell lung cancer (NSCLC), with extensive metastases in the lymph nodes, liver, skeleton, and cerebrum (TNM classification cT3N3M1c).