TY - JOUR AB - P40 and thyroid transcription factor‑1 (TTF‑1) dual expression in non‑small cell lung cancer (NSCLC) is a rare occurrence. However, the presence of EML4‑ALK and PIK3CA gene mutations in this type of cancer is unknown. The present study describes the case of a 38‑year‑old male patient who had never smoked. A 4.5‑cm mass adjacent to his right upper mediastinum was detected by a computed tomography (CT) scan of the chest. Biopsy of the level four lymph nodes in the right mediastinum revealed microscopic morphological features typical of high‑grade NSCLC. Immunohistochemical findings resembled those reported previously for several cases of NSCLC with the dual expression of P40 and TTF‑1 markers. In addition, echinoderm microtubule‑associated protein‑like 4‑anaplastic lymphoma kinase (EML4‑ALK) and phosphatidylinositol‑4,5‑bisphosphate 3‑kinase catalytic subunit a (PIK3CA) gene mutations were detected using high‑throughput next‑generation sequencing. To the best of our knowledge, this is the first report of NSCLC with the expression of P40 and TTF‑1 as well as EML4‑ALK and PIK3CA gene mutations. The presence of this type of tumor should be considered in patients with NSCLC who have never smoked and may have unique clinicopathological features. AD - Department of Respiratory Medicine, The First People's Hospital of Xiaoshan District, Hangzhou, Zhejiang 311200, P.R. China Department of Pathology, The First People's Hospital of Xiaoshan District, Hangzhou, Zhejiang 311200, P.R. China AU - Cai,Ying AU - Liu,Hongsheng AU - Chen,Xiaodan AU - Yang,Junjie AU - Huang,Bin DA - 2023/02/01 DO - 10.3892/ol.2022.13645 IS - 2 JO - Oncol Lett KW - P40 TTF‑1 double expression EML4‑ALK PIK3CA mutation lung cancer PY - 2023 SN - 1792-1074 1792-1082 SP - 59 ST - P40 and TTF‑1 double‑expressing non‑small cell lung cancer with EML4‑ALK and PIK3CA gene mutations: A case report and review of the literature T2 - Oncology Letters TI - P40 and TTF‑1 double‑expressing non‑small cell lung cancer with EML4‑ALK and PIK3CA gene mutations: A case report and review of the literature UR - https://doi.org/10.3892/ol.2022.13645 VL - 25 ER -