EGFR-RAD51 fusion variant in lung adenocarcinoma and response to erlotinib: A case report.

The most frequent epidermal growth factor receptor (EGFR) mutations of lung cancer include exon 19 in deletion and the exon 21 L858R mutation. And EGFR-tyrosine kinase inhibitor (TKI) as the standard first line treatment show good response to classical/sensitizing EGFR mutations. With the development of detection methods, some uncommon genomic mutation events such as exon 18-25 kinase domain duplications (KDD) and EGFR rearrangements (EGFR-RAD51 or EGFR-PURB) are found. We reported a case of EGFR-RAD51 fusion in non-small-cell lung cancer(NSCLC) and the efficacy of erlotinib to this type fusion of NSCLC patients. A 48-year-old Chinese man with right lung tumor and multiple brain metastases NSCLC (T1N2M1, stage IV). Histological examination of surgical specimens from the brain tumor showed lung adenocarcinoma metastasis. By using next generation sequencing assay, we found that tumor had EGFR-RAD51 fusion rather than the most common kind of EGFR mutations. Then the patient experienced a remarkable tumor response to erlotinib. Considering this rare EGFR fusion and remarkable response to TKI treatment, we conclude that the incidence of EGFR fusions in NSCLC patients should be attentive. NSCLC patients with EGFR-RAD51 fusion gene response to treatment with EGFR inhibitor. With the guidance of precise diagnosis, it is important that we should realize other rare EGFR gene mutations and novel diagnostic method.