The exact role of H. pylori in the induction of colon cancer is still a debate between the scientific researcher communities; this is attributed to the controversial results obtained. In previous studies, H. pylori were linked to the development of gastric cancer , while others reported paradoxical results showing no association between H. pylori and gastric cancer susceptibility [37–39]. However, reports from Sudan regarding the possible link between H. pylori and colon cancer are scarce. Therefore, in the present study, we examined the presence of H. pylori using immunohistochemistry technique on colon polyps and colon cancer lesions of Sudanese patients underwent colonoscopy.
The results obtained from this study showed a positive correlation between the presence of H. pylori infection and histopathological diagnosis, as H. pylori was prevalent in higher frequency in patients diagnosed with adenocarcinoma compared to those diagnosed as juvenile polyposis syndrome and the result was statistically significant. This result also agrees with studies conducted by Jones et al, and Grahn et al., they investigated the presence of H. pylori in 59 adenocarcinomas colon biopsies using immunohistochemistry, and 77 colon and rectum cancer cases using molecular technique, correspondingly [40, 41]. Jones et al., reported that H. pylori were detected in 10/59 adenocarcinoma cases representing about 16.9% of the total cancer cases studied . While, Grahn et al., showed that H. pylori were present in 27% of the cases; among the studied colon cancer, H. pylori were present in 11/42 (26%) cases .
Although, for several studies failed to demonstrate any association between H. pylori and colon cancer, or even if this microorganism can colonize the colon [42–46]. This could only be attributed to the ability of demonstrating the H. pylori bacteria in the various colon lesions of colitis, polyps and adenocarcinoma included in this study, which was achieved by the aid of the immunohistochemistry technique that allowed a better localization of H. pylori within the tissue sections.
Interestingly, several theories were proposed regarding the exact role by which H. pylori induced colon cancer, one hypothesis is that colon cancer can be induced by the produced H. pylori toxins; however, this theory was based only on serological data [39, 47–49]. Furthermore, some studies showed that colitis and colon cancer were also developed in experimental mice models infected with H. hepaticus . accordingly, the development of colon cancer seems most likely due to the interaction between toxins produced by the bacteria and the immune cells of the mice . Therefore, the results we obtained from our study showing that H. pylori were present, nevertheless, it means that H. pylori infection is responsible for the induction and the development of colon cancer, since the presence of H. pylori could be encountered as post-cancer incidence. This however, still requires more complicated experimental studies to investigate this hypothesis, yet, the role of H. pylori cannot be excluded due to this hypothesis. Therefore, this preliminary report needs further advanced experimental investigations to enable the determination on the exact mechanisms by which H. pylori can induce colon cancer.