Expression of p185erbB2 and p21ras in carcinoma, dysplasia, and intestinal metaplasia of the stomach: an immunohistochemical and in situ hybridization study

Investigation of vascular endothelial growth factor gene polymorphisms and its association with clinicopathologic characteristics in gastric cancer

OBJECTIVE

Vascular endothelial growth factor (VEGF) is known to be a potent proangiogenic factor. This study evaluates the potential association of three VEGF gene polymorphisms (-460T > C, +405G > C, and 936C > T) with the susceptibility to and clinicopathologic characteristics of gastric cancer.

METHODS

The VEGF genotypes were determined using paraffin-embedded tissue from 413 patients who underwent a surgical resection and peripheral blood lymphocytes from 413 healthy controls by PCR-RFLP assay.

RESULTS

There was no difference in the allele frequency of -460T > C polymorphism. However, for the +405G > C polymorphism, the +405C allele was associated with a significantly decreased susceptibility to gastric cancer [odds ratio (OR) 0.686; 95% confidence interval (CI) 0.564-0.834]. Although there was no significant difference in the distribution of the 936C > T polymorphism between the two groups, the 936T allele was associated with a decreased susceptibility to gastric cancer (OR 0.757; 95% CI 0.591-0.970). In the haplotype analyses, the haplotype TCT (OR 0.405; 95% CI 0.263-0.624) was most closely associated with a decreased susceptibility to gastric cancer. However, no significant association was observed between the frequency of the genotypes or alleles and the clinicopathologic characteristics of gastric cancer.

CONCLUSION

These observations imply that the VEGF gene polymorphisms may be associated with the susceptibility to gastric cancer. However, further studies of other VEGF sequence variants and their biological functions are needed to understand the role of the VEGF polymorphisms in determining the susceptibility to gastric cancer.

Review article: helicobacter pylori and molecular events in precancerous gastric lesions

Gastric cancer can be divided into intestinal type and diffuse type that differ substantially in epidemiology and pathogenesis. The most important aetiological factor associated both with intestinal and diffuse gastric cancer, is Helicobacter pylori. Exposure of gastric epithelial cells to H. pylori results in an inflammatory reaction with the production of reactive oxygen species and nitric oxide that, in turn, deaminates DNA causing mutations. The complex interplay between H. pylori strain, inflammation and host characteristics may directly promote diffuse type gastric cancer or induce a cascade of morphological events, i.e. atrophy, intestinal metaplasia and dysplasia, finally leading to intestinal type gastric cancer. Two mechanisms, genetic and epigenetic have been held to play a role in the molecular alterations underlying gastric carcinogenesis. The former, comprising changes in the DNA sequence, is irreversible; the latter, involving DNA methylation, is potentially reversible by eliminating the triggering agents. If H. pylori is eradicated before development of stable mutations, the risk of gastric cancer will likely be prevented. Thus, eradication of H. pylori might immediately reduce the risk of diffuse type gastric cancer, whereas prevention of intestinal type gastric cancer may be less effective if patients are treated later in the evolution of the carcinogenic process.