Background/AimsThe purpose of this study was to evaluate the clinicopathologic characteristics of colon cancers detected at the SOK Sokpeynhan Internal Medical Network, a nationwide system of primary health care institutions.MethodsWe analyzed 579 colon cancer patients diagnosed using colonoscopy at the SOK network from January 2011 through December 2012. Cancers from the rectum to the splenic flexure were classified as left colon cancer. Patients over 65 were classified as senior.ResultsThe mean age (±SD) of subjects was 60.9±10.5 years and 61.1% were men. More than one quarter (28.2%) of patients were asymptomatic. The prevalence of left colon cancer was higher (77.9%) than that for right colon cancer. The most frequent macroscopic and histologic types were depressed (58.9%) and moderately differentiated adenocarcinoma (52.2%), respectively. Asymptomatic subjects displayed protruding or well differentiated adenocarcinoma, while symptomatic patients were more likely to display depressed or moderately differentiated adenocarcinoma (P<0.05). The mean age of the right colon cancer group was higher than that for the left colon cancer group (P<0.05). Among symptomatic patients, the most frequent symptoms were bloody stool for patients with left colon cancer and abdominal discomfort for patients with right colon cancer (P<0.05). The prevalence of depressed cancer was higher in older subjects as compared to younger subjects (P<0.05). The prevalence of right colon cancer tended to increase with age, although this difference did not achieve statistical significance (P>0.05).ConclusionsStudy results indicated an increase of colon cancer amongst younger demographics in recent years. The effectiveness of colonoscopy screening was also evident, as asymptomatic patients demonstrated frequent findings of well differentiated adenocarcinomas. Study results also suggested a need for closer examination of older patients, as right colon cancer tended to increase with age.

Our animal study showed that H. pylori infection induced COX-2 expression and increased prostaglandin concentration. Administration of NSAIDs decreased the prostaglandin concentration, but did not increase mucosal damage in H. pylori-induced gastritis. Selective COX-2 inhibitors, instead of conventional NSAIDs, had no beneficial effect on preventing mucosal damage in H. pylori-induced gastritis.

To investigate the potential implication of the subtype of intestinal metaplasia in the progression to the gastric carcinoma, we analyzed the mutations of the p53 gene and microsatellite instability (MSI) both in the complete type (type I) and in the sulphomucin-secreting incomplete type (type III) intestinal metaplasia located adjacent to the gastric carcinoma. p53 mutations were observed in 13.3% of type I, in 6.6% of type III intestinal metaplasia, and in 40% of gastric carcinoma. The difference between p53 mutations observed in type I and type III intestinal metaplasia was not statistically significant. No identical mutation of the p53 gene was found in the intestinal metaplasia and carcinoma specimens from the patients. There was no case of intestinal metaplasia showing MSI. In gastric carcinomas, MSI was observed in six cases (40%). The cases harboring BAT-26 instability did not have the mutation of the p53 gene. These data suggest that intestinal metaplasia adjacent to gastric carcinoma, irrespective of its subtype, do not have the genetic alterations as showing in their carcinoma tissues.

In vitro subcultures of bacteria can lead to genetic and phenotypic changes. This study aimed at investigating the effect of repeated subcultures on the adhesion, motility, cytotoxicity, and gastric inflammation caused by Helicobacter pylori. H. pylori SS1 strain was subcultured 64 times on agar plates containing Brucella broth and 5% bovine calf serum. The adhesion, motility, cytotoxicity, and gastric inflammation produced in Mongolian gerbils were compared between the first and 64th subcultured strain. The adhesion rates, following 3 hr exposure of AGS cells to either the first strain or the 64th-transferred strain, were 21% and 12%, respectively. The motility of the 64th-transferred strain decreased significantly when compared to the 1st strain (9.1 mm vs. 15.1 mm). The cytotoxicity index tended to be higher in the first strain than in the 64th-transferred strain (73.7% vs. 69.2%). The initial infection rate on the gerbils showed no difference between the two strains. However, chronic gastric inflammation of the first strain-infected gerbils was somewhat more severe than that of the 64th-transferred strain-infected gerbils. Therefore, the use of repeatedly subcultured strains of H. pylori in virulence experiments can lead to different results from thoses of the original strain.

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