Investigators have also researched other potential indicators including tumor PD‐L1 expression, epidermal growth factor receptor (EGFR) mutation status, anaplastic lymphoma kinase (ALK) status, c‐ros oncogene 1 (ROS1) status, B‐Raf proto‐oncogene (BRAF) mutation status, mesenchymal epithelial transition (MET) status, and KRAS proto‐oncogene (KRAS) mutation status; trials have yielded conflicting results.12, 13, 14. The gene discussed is ALK; the disease is neoplasm.