Helicobacter pylori cagA,iceA and vacA genotypes in patients with gastric cancer in Taiwan

AIM: Helicobacter pylori( H pylori) has been linked to chronic gastritis, peptic ulcer, gastric cancer and MALT-lymphoma.The link of genotypes of Hpylorito gastric cancer remains controversial. The aim of this study was to investigate the Hpylori vacA alleles, cagA and iceA in patients with gastric cancer in Taiwan.METHODS: Patients with gastric cancer, peptic ulcer and chronic gastritis were enrolled in this study. We obtained biopsy specimens from the stomach at least 2 cm away from the tumor margin in patients with gastric cancer, and from the antrum of stomach in patients with peptic ulcer or chronic gastritis. DNA extraction and polymerase chain reaction were used to detect the presence or absence of cagA and to assess the polymorphism of vacA and iceA.RESULTS: A total of 168 patients (gastric ulcer: 77, duodenal ulcer: 66, and chronic gastritis: 25) were found to have positive PCR results of the biopsy specimens from patients with peptic ulcer and chronic gastritis. We found positive cagA (139/168, 83%), m2 (84/168, 50%) and iceA1 (125/168,74%) strains in the majority of patients. In patients with gastric cancer, the vacA sla and slc subtypes were less commonly found than those in non-cancer patients (35/66 vs 127/168, P= 0.0001 for sla and 13/66 vs93/168, P<0.0001 for slc). In the middle region, the mlT strain in patients with gastric cancer was more than that of non-cancer patients(23/66 vs 33/168, P = 0.02).CONCLUSION: In Taiwan, H pylori with positive vacA sla,cagA and iceA1 strains are found in the majority of patients with gastric cancer or non-cancer patients. In patients with gastric cancer, the vacA s1a and slc subtypes are less and m1T is more than in patients with peptic ulcer and chronic gastritis.

Elevated level of spindle checkprotein MAD2 correlates with cellular mitotic arrest,but not with aneuploidy and clinicopathological characteristics in gastric cancer

AIM: To study the relevance of spindle assembly checkprotein MAD2 to cellular mitotic status, aneuploidy and other clinicopathological characteristics in gastric cancer. METHODS: Western blot analyses were performed to analyze the protein levels of MAD2 and cyclin B1 in the tumorous and adjacent nontumorous tissues of 34 gastric cancer patients. Cell cycle distribution and DNA ploidy of cancer tissues were also determined by flow cytometry. Conventional statistical methods were adopted to determine the relevance of abnormal MAD2 level to mitotic status, aneuploidy and clinicopathological parameters. RESULTS: Out of 34 gastric cancer patients 25 (74%) exhibited elevated MAD2 levels in their tumorous tissues compared with the corresponding nontumorous tissues. Elevation of MAD2 levels significantly correlated with the increased levels of cyclin B1 expression and G2/M-phase distribution (P=0.038 and P=0.033, respectively), but was not relevant to aneuploidy. The gastric cancer patients with elevated MAD2 levels showed a tendency toward better disease-free and overall survival (P>0.05). However, no association was found between elevated MAD2 levels and patients' clinicopathological characteristics. CONCLUSION: Elevation of MAD2 level is present in 74% of gastric cancer patients, and correlates with increased mitotic checkpoint activity. However, elevation of MAD2 level is not associated with patients' aneuploidy and any of the clinicopathological characteristics.