Epsilon Archive for Student Projects

Abstract

Syfte: Undersöka om livsmedelsburna patogener bidrar till utveckling av kolorektalcancer.
Metod: Aktuellt arbete baserades på en litteraturundersökning med syftet att hitta orginalartiklar fokuserade på en eller flera av fyra förutbestämda patogener (Campylobacter spp.; Salmonella spp.; E. coli; L. monocytogenes), i kombination med kolorektalcancer. Inkluderade artiklar skulle ha designen exponering – utfall. En eventuell koppling mellan patogen och kolorektalcancer involverar någon slags biokemisk aktivitet, således inkluderades studier på relaterade mekanismer. Som databaser användes ”PubMed” och ”Web of Science”.
Resultat: Sexton artiklar inkluderades. Flera studier indikerade att exponering för en aktuell patogen, alternativt ett bakteriellt ämne, leder till någon form av tumörfrämjande aktivitet in vivo (mus) och in vitro (mus, human). Föreslagna mekanismer inkluderade modifierade receptorer, inducerad neutrofil differentiering till alternativ subtyp, förändrade proteinuttryck, inducerad DNA-skada respektive modifierade signalvägar. Största delen av inkluderade artiklar var fokuserade på Salmonella. En populationsbaserad studie påvisade en koppling mellan ökad koloncancerincidens och tidigare salmonellainfektion. En annan studie kunde dock inte bekräfta en signifikant koppling mellan tidigare salmonellapatienter och ökad risk för koloncancer. En studie, som dock inte inkluderade någon infektionsdata vid baslinjen, fann ingen förhöjd koloncancerincidens hos personer i yrken med högre infektionsrisk (zoonotiska sjukdomar) jämfört med personer i andra yrken.
Slutsats: Baserat på resultaten från de inkluderade studierna kan livsmedelsburna patogener eventuellt bidra till utveckling av kolorektalcancer. Ämnet är dock komplext och det finns ett behov av mer forskning inom området.

Objectives: To investigate the potential connection between infection with food-borne pathogens and the subsequent development of colorectal cancer.
Methods: This paper was conducted based on a literature review, searching for original studies focusing on one or several of pre-determined pathogens (Campylobacter spp.; Salmonella spp.; E. coli; L. monocytogenes) and colorectal cancer. Included articles had to have an exposure – outcome design. If indeed a connection between pathogen and colorectal cancer is observed, it would have to be accompanied by a biochemical mechanism, even if not presented. Therefore, research on related mechanisms, such as the effects of specific bacterial toxins on cellular function, was also included. Data bases used were PubMed and Web of Science.
Results: Sixteen articles were ultimately included. Several studies indicated that exposure to one of the included bacteria, or a bacterial agent, showed an increase in pro-tumor activity in vivo (mice) and in vitro (mice, human). Suggested mechanisms included modified receptors, induced neutrophil differentiation to a subtype variant, altered protein expressions, induced DNA damage, and modified signal pathways, among others. Most of the articles were focused on Salmonella. One population-based study found an association between increased colon cancer incidence and previous Salmonella infection. However, another similar study did not confirm any signific connection between earlier Salmonella infection and increased risk of colon cancer development. One study, although not including any baseline infection data, found no significantly increased colon cancer incidence between occupations with a higher infection risk (zoonotic diseases) and other occupations.
Conclusion: Based on the results within included studies, food-borne pathogens may have a role in the development of colorectal cancer. However, the subject is complex, and there is a need for more research in this area.