Colorectal Cancer and Gut Microbiota

Abstract

Colorectal cancer is the third most diagnosed cancer globally, accounts for 9.6% 0f all cancer diagnosed and 9.3% of all cancer deaths. Most cases of colorectal cancer, about 80% are sporadic in origin, and the remaining 20 % are hereditary. Colorectal cancer have  the risk factors like family history, diet, comorbities, smoking, alcohol, medication research also shows that there is alteration in the gut microbiota of colorectal cancer. Gold standard investigation for diagnosis of colorectal cancer is colonoscopy with biopsy for histopathology. Human gut microbiota is the colony of comprises more than 10¹⁴ microbes like bacteria, virus and fungi. The normal commensal microorganism present in the gut microbiota have symbiotic association with the intestine helps in digestion and absorbtion. Colorectal cancer as it involve chronic inflammatory response leads to decrease in the biodiversity of microorganism and presence of pathological microorganism and this is used as a biomarker for the colorectal cancer. Fecal sample metagenomic analysis shown increase in Fusobacterium nucleatum, Parvimonas, Peptostreptococcus, Porphyromonas, and Prevotella, are part of the CRC microbiota. This is a promising noninvasive biomarker for colorectal cancer.

Keywords: Colorectal cancer, Gut microbiota, Fusobacterium nucleatum, Bacteroides fragilis