Arginine and proline alleles of the p53 gene are associated with different locations of gastric cancer

Background/Aims: Abnormal function of gene p53 is associated with the formation of various cancers including gastric cancer. Recently, p53 codon 72 polymorphism was extensively studied to determine the risk factors responsible for cancer formation using the concept of single nucleotide polymorphism. In this study, we evaluated the risk factors associated with p53 codon 72 polymorphism and gastric cancer carcinogenesis. Methodology: This study consisted of 51 patients and 59 control subjects. We then evaluated the patient's age, sex, smoking and alcohol consumption habits, tumor location, cell differentiation, lymph node involvement, distant metastasis and tumor stage. Finally the p53 gene codon 72 polymorphism was analyzed by polymerase chain reaction (PCR). The results of polymorphic genotype were stratified with the above risk factors and the associations were analyzed. Results: There was no significant difference between the polymorphic genotypes and the two study groups. However, when the genotypes were further stratified with co-factors, the results revealed a significant association with tumor location. The proline homozygote was more frequent in the patients with gastric cancer at the cardia than in those with cancer at the antral or corpus locations. (55.56% of cardia vs. 14.28% of corpus and antrum, p=0.024). The arginine allele was associated with antral and corpus location of gastric cancer and the proline allele was associated with cardial location (OR=3.25, p=0.026). Also, these polymorphisms do not seem to be associated with age, sex, smoking and alcohol consumption, cell differentiation, lymph node involvement, tumor stage and distant metastasis. Conclusions: The proline allele at p53 codon 72 is associated with adenocarcinoma of the gastric cardia, and the arginine allele is associated with cancer of the antral and corpus locations. These findings suggest that different genotypes of the p53 gene in different locations of stomach might implicate a different cause of tumor growth.