<b>Characteristic Changes of Gut Microbiome on the Surface of Tissues during the Progression in Colorectal adenoma-carcinoma sequence</b>

The microbiome of the mucous layer in the intestines directly interacts with the intestinal epithelium and is closely associated with the development of colorectal cancer. By using endoscopic cell brush sampling and 16s rRNA gene sequencing, we directly examined the gut microbiome interacting with the tumor surface, providing more accurate insights compared to traditional fecal samples. This approach allowed us to identify unique changes in gut microbiome at different pathological stages of colorectal cancer formation and observe distinct clustering patterns in the intestinal microbiome. Our study found that in the adenoma-carcinoma sequence of colorectal cancer, the microbiome on the surface of tumor tissue continuously changes as the adenoma progresses to carcinoma. That is, as the malignancy of the tumor increases, the beneficial bacteria on the tumor surface gradually decrease while the pathogenic microorganisms continuously increase.