Comparative epidemiology of gastric cancer between Japan and China

AIM:To clarify the similarities and differences in gastric cancer epidemiology between Japan and China.METHODS:A comprehensive literature search of the PubMed database was performed.The relevant literature published in China was also been cited.Data on incidence and mortality rates in 2008 were obtained from the Cancer Mondial database,published by International Agency for Research on Cancer at http://www-dep.iarc.fr/.RESULTS:Gastric cancer remains a significant publichealth burden in both Japan and China.The prevalence of Helicobacter pylori(H.pylori)colonization is high in the adult populations of both countries.Accumulating evidence from intervention studies in both countries has shown the effectiveness of H.pylori eradication in reduc-ing gastric cancer incidence.There are differences,however,in many aspects of gastric cancer,including patterns of incidence and mortality,trends in the prevalence of H.pylori infection,H.pylori strains,the magnitude of risk of gastric cancer related to H.pylori infection,and associations with dietary habits.Compared with China,Japan has seen a more rapid decline in H.pylori infection among adolescents.While Japanese cohort studies have dominated the literature concerning the associations between gastric cancer and dietary habits,numerous case-control studies in China suggest a positive association between a high intake of preserved fish and vegetables and gastric cancer risk.There is a need for a multidisciplinary research approach to understand the interactions between various strains of H.pylori,host factors,and other lifestyle and environmental factors in gastric carcinogenesis in both countries.CONCLUSION:The shared high incidence of gastric cancer and high prevalence of H.pylori,as well as differences in many aspects of gastric cancer,provide an excellent opportunity to establish Sino-Japanese collaborations.

Genetic Polymorphisms in ADH1B and ALDH2 Are Associated with Colorectal Tumors in Japan: A Case-Control Study

Background: Unlike with esophageal cancer, acetaldehyde levels and genetic polymorphisms in alcohol dehydrogenase have not yet been shown to be contributing factors for colorectal cancer (CRC). This study aimed to clarify the mechanism of CRC development related to alcohol consumption and to the presence of genetic polymorphisms in the alcohol dehydrogenase, ADH1B and aldehyde dehydrogenase, ALDH2. Methods: This was a case-control study (221 cases and 179 controls) in patients with adenomas and intramucosal tumors who underwent endoscopic removal of all tumors. The amount of alcohol consumption was determined using a self-recorded questionnaire, and the tumor information was obtained from colonoscopy results. Blood samples were taken to analyze the following polymorphisms: ALDH2 Glu504Lys and ADH1B His48Arg. Results: The polymorphisms in ADH1B and ALDH2 had little influence on the development of colorectal adenoma or intramucosal cancer. Patients with ALDH2 (Glu/Glu) were more tolerant of alcohol than those with ALDH2 (Glu/Lys and Lys/Lys). Next, we examined certain combinations of the ADH1B genotypes. In the ALDH2 (Glu/Glu) group, an increased risk (OR = 3.4;95% CI 1.4 - 8.4;P = 0.009) was observed among moderate/heavy drinkers with ADH1B (His/His). In the ALDH2 (Glu/Lys and Lys/Lys) group, an increased risk (OR = 4.2;95% CI 1.1 - 16.7;P = 0.041) was found among moderate/heavy drinkers with ADH1B (Arg/His and Arg/Arg). Conclusions: ADH1B and ALDH2 activity may be involved in the development of CRC.

Three novel NEIL1 promoter polymorphisms in gastric cancer patients

AIM:To identify genetic polymorphisms in the promoter region of the human base excision repair gene NEIL1 in gastric cancer patients.METHODS:The NEIL1 promoter region in DNA from 80 Japanese patients with gastric cancer was searched for genetic polymorphisms by polymerase chain reaction-single-strand conformation polymorphism and subsequent sequencing analyses.RESULTS:Three novel genetic polymorphisms,i.e.c.-3769C>T,c.-3170T>G,and c.-2681TA[8],were identified in the NEIL1 promoter region at an allele frequency of 0.6%,9.4%,and 4.4%,respectively,in Japanese gastric cancer patients.CONCLUSION:Three NEIL1 promoter polymorphisms detected in this study may be of importance in gastric carcinogenesis.