In early-stage NSCLC, the data showed that the levels of miR-182, miR-183, and miR-210 were significantly distinct between NSCLC patients and tobacco smokers, with AUCs of 0.728, 0.787, and 0.748; sensitivities of 67.8%, 74.7%, and 55.2%; and specificities of 90.0%, 80.0%, and 90.0%, respectively (P < 0.0001, < 0.0001, and < 0.0001; 95% CI: 0.634–0.810, 0.698–0.861, and 0.655–0.827; S1 Fig), whereas the levels of miR-126 and CEA had no obvious difference in AUCs to distinguish NSCLC and tobacco smokers (P = 0.1205, 0.4240; S1 Fig). The gene discussed is CEACAM5; the disease is non-small cell lung carcinoma.