Oral and colonic microbiomes and colon cancer

Oral microbiota includes bacteria, fungi, protozoa, and viruses, which can translocate by the digestive tract and may favor the development of local benign or malignant pathology. Some researchers have studied the physiopathological mechanisms involving the role of oral microorganisms in intestinal diseases. Two major areas of these studies are colorectal cancer and COVID-19. Some of the intestinal manifestations of this pandemic may be associated with dysbiosis. Both sinergistic and antagonistic bacterial and fungal associations have been described in patients with colorectal cancer, characterizing dysbiosis. Oral microbes can cause opposite effects to the beneficial intestinal flora, eliciting DNA epithelial damage and apoptosis in the bowel as tumor triggering factors. Fusobacterium nucleatum and P. gingivalis were emphasized among the most often oral microorganisms found increased in evaluations of colorectal cancer. The recent advent of new biomarkers to diagnose colorectal tumor is also considered. The aim of these comments is to emphasize the usefulness of the more recent findings. Keywords: Colorectal cancer; Dysbiosis; Microbiota; Mycobiota