MLH1 and colorectal carcinoma: Another study demonstrated that B. fragilis, E. coli, F. nucleatum, and K. pneumoniae were significantly enriched in CpG island methylator phenotype-positive (CIMP-positive) cases and were associated with methylation of the MutL homolog 1 gene after analyzing 203 CRC patients samples, indicating that specific bacteria may drive CRC progression by altering CpG island methylation [98].