A Novel Oncogenic Driver in a Lung Adenocarcinoma Patient Harboring an -KDD and Response to Afatinib.

Oncogenic mutations in the epidermal growth factor receptor () occur frequently in patients with lung cancer. These mutations may serve as critical predictive biomarkers in patients with non-small cell lung cancer (NSCLC). Among them, exon 18-25 kinase domain duplication (-KDD) mutations have been identified as a novel gene subtype in NSCLC. We reported a rare case of a 59-year-old male diagnosed with adenocarcinoma. A biopsy revealed an -KDD identified by the next generation sequencing (NGS). Effective treatment outcome has been observed after administration with afatinib. This case highlights that comprehensive NGS technique is valuable in detecting novel genetic mutations in tumors.