Association between colorectal cancer, the frequency of Bacteroides fragilis, and the level of mismatch repair genes expression in the biopsy samples of Iranian patients

• Published in: BMC gastroenterology Vol. 24; no. 1; p. 82
• Main Authors: Nazarinejad, Nooshin, Hajikhani, Bahareh, Vaezi, Amir Abbas, Firoozeh, Farzaneh, Sameni, Fatemeh, Yaslianifard, Somayeh, Goudarzi, Mehdi, Dadashi, Masoud
• Format: Journal Article
• Language: English
• Published: England BioMed Central 23.02.2024; BMC
• Subjects: Bacteroides fragilis; Bacteroides fragilis - genetics; Bacteroides fragilis - metabolism; Biopsy; Colon cancer; Colonoscopy; Colorectal cancer; Colorectal carcinoma; Colorectal Neoplasms - pathology; Colorectal Neoplasms, Hereditary Nonpolyposis - diagnosis; Colorectal Neoplasms, Hereditary Nonpolyposis - genetics; Colorectal Neoplasms, Hereditary Nonpolyposis - pathology; DNA Mismatch Repair - genetics; DNA repair; DNA-Binding Proteins - genetics; Gene expression; Humans; Investigations; Iran; Microsatellite Instability; Mismatch repair; mlh1; MLH1 protein; msh2; MSH2 protein; msh6; MSH6 protein; Mutation; MutL Protein Homolog 1 - genetics; MutL Protein Homolog 1 - metabolism; MutS Homolog 2 Protein - genetics; MutS Homolog 2 Protein - metabolism; Tumorigenesis; Tumors; Variance analysis; Women; Iran; msh2; mlh1; Bacteroides fragilis; Colorectal cancer; msh6
• ISSN: 1471-230X; 1471-230X
• DOI: 10.1186/s12876-024-03169-z

Deficient DNA mismatch repair (MMR) can cause microsatellite instability (MSI) and is more common in colorectal cancer (CRC) patients. Understanding the carcinogenic mechanism of bacteria and their impact on cancer cells is crucial. Bacteroides fragilis (B. fragilis) has been identified as a potential promoter of tumorigenesis through the alteration of signaling pathways. This study aims to assess the expression levels of msh2, msh6, mlh1, and the relative frequency of B. fragilis in biopsy samples from CRC patients. Based on the sequence of mlh1, msh2, and msh6 genes, B. fragilis specific 16srRNA and bacterial universal 16srRNA specific primers were selected, and the expression levels of the target genes were analyzed using the Real-Time PCR method. Significant increases in the expression levels of mlh1, msh2, and msh6 genes were observed in the cancer group. Additionally, the expression of these MMR genes showed a significant elevation in samples positive for B. fragilis presence. The relative frequency of B. fragilis in the cancer group demonstrated a significant rise compared to the control group. The findings suggest a potential correlation between the abundance of B. fragilis and alterations in the expression of MMR genes. Since these genes can play a role in modifying colon cancer, investigating microbial characteristics and gene expression changes in CRC could offer a viable solution for CRC diagnosis.