The risk of LUSC was 8.119 times higher in men than in women and 5.753 times higher in patients with a smoking history than in those without a smoking history. In addition, the risk of LUSC increased by 0.913-fold for each 1-unit increase in CEA and 1.801-fold for each 1-unit increase in SCCA. Among the four variables, gender (P=0.018) and smoking history (P=0.011) could be used as independent risk factors to distinguish NSCLC subtypes, and the results of stepwise regression are shown in Figure 5. The gene discussed is CEACAM5; the disease is non-small cell lung carcinoma.