Investigation of 16 s rRNA sequencing of increased F. nucleatum levels in mucosal or fecal samples of CRC patients has shown that F. nucleatum levels in CRC tissue is associated with the tumor site of right-sided proximal colorectum and CpG island methylator phenotype (CIMP) status, microsatellite instability (MSI) and mutations in BRAF, KRAS, CHD7, CHD8 and TP53 genes [131]. Here, KRAS is linked to colorectal carcinoma.