ALK and lung cancer: To investigate whether the FR could be used as an independent prognostic predictor in NSCLC, as shown in Table 2, we converted the risk factors associated with lung cancer prognosis into two-category variables for stratified analysis, including sex (male/female), age (<60 years old/≥60 years old), pathological grade (I–II grades/III grade), tumor size (≤5 cm/>5 cm), T stage (T1-T2/T3-T4), N stage (N0/N1-N3), AJCC stage (I–II/III–IV), adenocarcinoma EGFR gene status (wild type/mutant type), and ALK gene status (wild type/mutant type).