ROC curve analysis showed that the CD4+/CD8+ ratio had an AUC of 0.712 (95%CI: 0.575‐0.849, P=0.008) for differentiating lung cancer from pulmonary infection, with a sensitivity of 56.76% and a specificity of 85.00%; the nCD64 index had an AUC of 0.677 (95%CI: 0.539‐0.814, P=0.026), with a sensitivity of 44.74% and a specificity of 95.24%. This evidence concerns the gene CD4 and lung cancer.