Genomic analysis identifies association of <i>Fusobacterium</i> with colorectal carcinoma

TLDR

The colorectal carcinoma tumor microenvironment contains altered cancer cells, nonneoplastic cells, and diverse microorganisms, yet the microbiota’s role in carcinogenesis remains poorly understood. The study characterizes the colorectal carcinoma microbiota composition using whole‑genome sequencing of nine tumor/normal pairs. The authors employed whole‑genome sequencing of nine tumor/normal pairs and fluorescence in situ hybridization to identify and localize Fusobacteria within colorectal tumors. Fusobacterium is enriched in colorectal carcinomas, confirmed by qPCR and 16S rDNA analysis of 95 tumor/normal pairs, while Bacteroidetes and Firmicutes are depleted, indicating microbiota alterations whose role in carcinogenesis remains to be clarified.

Abstract

The tumor microenvironment of colorectal carcinoma is a complex community of genomically altered cancer cells, nonneoplastic cells, and a diverse collection of microorganisms. Each of these components may contribute to carcinogenesis; however, the role of the microbiota is the least well understood. We have characterized the composition of the microbiota in colorectal carcinoma using whole genome sequences from nine tumor/normal pairs. Fusobacterium sequences were enriched in carcinomas, confirmed by quantitative PCR and 16S rDNA sequence analysis of 95 carcinoma/normal DNA pairs, while the Bacteroidetes and Firmicutes phyla were depleted in tumors. Fusobacteria were also visualized within colorectal tumors using FISH. These findings reveal alterations in the colorectal cancer microbiota; however, the precise role of Fusobacteria in colorectal carcinoma pathogenesis requires further investigation.