Epidermal growth factor receptor mutation p.A864V in small cell lung cancer and lung squamous cell carcinoma: a case report and review of literature.

Mutations in the epidermal growth factor receptor ( EGFR ) have been identified in 10-20% of nonsmall cell lung cancer (NSCLC), specifically lung adenocarcinomas. However, these mutations have rarely been reported in small cell lung cancer (SCLC) and lung squamous cell carcinoma (LUSC). Treatment for SCLC and LUSC patients has not yet been established. We present a rare case of p.A864V mutation in Exon 21 of EGFR gene in a patient with both SCLC and LUSC, which is the first case of such mutation type in lung cancer in the world. The patient was a 55-year-old female nonsmoker with stage IV SCLC and LUSC, gene sequencing revealed EGFR gene mutation, she refused EGFR tyrosine kinase inhibitors (TKIs) targeted therapy and received conservative treatment, which led to disease progression. In conclusion, clinicians should be aware of the possibility of the rare EGFR mutations. Platinum-based chemotherapy can be treated for SCLC and LUSC patients.