miRNAs are valuable for the diagnosis and prognosis prediction of CRC patients.59,60 Gut microbiota can regulate processes of CRC such as proliferation, drug resistance, and metastasis through miRNAs.61–63 Some studies have shown that miRNAs can enter bacteria, specifically regulating gene transcription and affect bacterial growth.41 Additionally, KRAS mutations can facilitate tumorigenesis by impacting several steps, including processing of miRNA.64 It appears that tumors and the gut microbiota have formed a close connection through miRNAs. This evidence concerns the gene KRAS and colorectal carcinoma.