To investigate association between tumor necrosis factor-alpha-308 polymorphism(TNF-α-308) and serum level of pepsinogen (PG) in patients with gastric cancer.

Human DNA samples were obtained from patients with gastric cancer (n=500) and people who have conducted health examination (n=500). All subjects were genotyped by polymerase chain reaction-restriction fragement length polymorphism analysis. Frequencies of genotypes and alleles were analyzed. TNF-α-308 in relation with the serum level of PG.

Frequency of genotype and allele were 74.60%(373/500), 22.40%(112/500), 3.00%(15/500), 85.80% (858/1 000) and 14.20%(142/1 000) in patients with gastric cancer respectively, and 79.20%(396/500), 19.00%(95/500), 1.80%(9/500), 88.70%(887/1 000) and 11.30%(113/1 000) in health group respectively. There was no significant difference between the two groups (χ²=3.584, 1.713; P>0.05). Compared with health group TNF-α, PGI, PGII and PGI/PGII in patients were (1.03±0.31) μg/L, (84.24±24.81) μg/L, (23.04±4.95) μg/L and 3.85±1.49, which demonstrated a significant difference between the two groups (Z=23.614, t=28.882, 8.240, 22.363; P<0.01). TNF-α, PGI and PGI/PGII ratios in patients of different genotypes(F=180.511, 72.840, 36.110 ) and clinical stages of different genotypes in gastric cancer (F=34.378, 30.981, 26.084) were significantly different (P<0.01), but no significant difference was noticed in the level of PGII (P>0.05). Pearson analysis showed that the level of TNF-α had negative correlation with PGI and PGI/PGII respectively (r=-0.748, -0.704; P<0.01).

TNF-α-308 polymorphism is unlikely to directly cause gastric cancer, whereas it may be involved in the occurrence and development of gastric cancer. The change of TNF-α level which affect the serum level of pepsinogen in patients with gastric cancer through TNF-α level, so that the PGI and PGI/PGII ratios of different genotypes and clinical stages of different genotypes in gastric cancer patients are significantly different, Therefore, when PG is applied in screening and diagnosis of gastric cancer, considerations should be given to the effects of TNF-α on PG regulation.