Therefore, for patients who are initially suspected of having lung carcinoma, if the imaging findings show several different manifestations of lung lesions, such as masses or nodules, bronchovascular bundle thickening, interlobular septa thickening, pleural thickening, bronchiectasis, round-shaped GGOs, diffuse GGOs and consolidation, and the concentrations of NSE, CYFRA 21-1, CEA, and CA125 are within normal limits or are slightly elevated, the serological level of IgG4 should be detected. This evidence concerns the gene CEACAM5 and lung carcinoma.