Table 1 demonstrates the difference between the serum levels of the two groups according to UICC staging in each tumour marker examined based on the results of the Mann–Whitney U-test. The serum CEA levels were not significantly different between any two groups. The serum CYFRA 21-1 and CA 15-3 levels were significantly different between all pairs of groups except 0 vs I–IV, although the P-values for CA 15-3 were a little smaller than those for CYFRA 21-1. This evidence concerns the gene CEACAM5 and neoplasm.