ALK and non-small cell lung carcinoma: In the treatment and prognosis of NSCLC, known biomarkers such as epidermal growth factor receptor (EGFR) mutations, Kirsten Rat Sarcoma Viral Oncogene mutations, anaplastic lymphoma kinase rearrangements, and the level of programmed death-ligand 1 (PD-L1) expression play important roles.