POLYMORPHISM OF THE TP53 GENE IN PATIENTS WITH GASTRIC CANCER IN PROSPECTIVE AND CLINICAL CASE-CONTROL STUDIES

Abstract

Background.A functionally significant TP53Arg72Pro polymorphism can contribute to the development of gastric cancer (GC).The aim:to study the associations of genotypes and alleles of the TP53Arg72Pro 4 polymorphism with GC and biomarkers of gastric ucosal atrophy in population-based prospective and case-control clinical trials among the population of Siberia.Material and methods.As a part of the epidemiological study, data of the international multicenter HAPIEE project for 2003–05, based on a population sample of residents of Novosibirsk city (serum and DNA samples) and data of the population-based registry of GC (2012) were compared. Gastric cancer patients were matched by age and sex to HAPIEE population controls. A total of 156 serum samples (GC – 52, control – 104) and 146 DNA samples (GC – 50, control – 96) were available for prospective analysis. DNA samples from 80 gastric cancer patients (45 men and 35 women, mean age 61.0 ± 13.4 years) and from 87 age-and sex-matched controls were analyzed. DNA samples from venous blood were genotyped according to standard methods. Serum samples were tested using diagnostic kit for enzyme-linked immunosorbent assays to determine the levels of pepsinogen I (PGI), PGII, PGI/PGII ratio, gastrin-17 and IgG antibodies to H. pylori.Results.No differences in genotype and allele frequencies of the TP53 gene between the case group and the control group were found. A decreased frequency of the Pro allele in female gastric cancer patients compared with controls indicated that the Pro allele is protective against the development of gastric cancer, but this effect was not observed in male patients. No associations of TP53 genotypes with the risk of diffuse or intestinal gastric cancer, as well as with the age and sex of patients were found. A high frequency of genotypes with the Pro allele in patients with stage III–IV gastric cancer indicated the relationship between Arg/Pro TR53 and tumor progression, in particular, the contribution of the minor Pro allele to the unfavorable prognosis. A prospective study showed high risk of reducing the level of pepsinogen for assessing predisposition to gastric cancer.Conclusion.Two case-control studies (population and clinical) conducted in the Western Siberia found no relationship between the TP53Arg72Pro polymorphism and the risk of gastric cancer. However, the TP53 genotype with a rare Pro allele was associated with atrophic gastritis and severity of gastric cancer.