A total of 482 NSCLC specimens with ALK gene status evaluated by FISH were collected and stored in the Biobank of Korea University Guro Hospital between 2012 and 2018. The glass slides were reviewed for histological diagnosis and immunohistochemical features, including ALK (5A4; Novocastra), TTF-1 (8G7G3/1; Dako; Agilent Technologies, Inc.), and napsin A (polyclonal; Cell Marque). The formalin-fixed paraffin-embedded (FFPE) tissue blocks of 10 patients, stored for <3 years to minimize the degradation of DNA and RNA, were selected for NGS analysis, and consisted of five ALK FISH-positive and five ALK FISH-negative adenocarcinomas (38 (link),39 (link)). The clinical information included age, sex, smoking history, cancer stage according to the 8th Edition of the American Joint Committee on Cancer staging manual, genetic mutation status and survival. All the glass slides, paraffin blocks and clinical information were provided by the Human Biobank of Korea University Guro Hospital, which collects patients' samples and medical information at the time of biopsies or surgical excisions of their tumors, with the written informed consent for future research use. The present study was conducted with the approval of the Institutional Review Board of Korea University Guro Hospital (approval no. 2018GR0357).