MLH1 and cancer: When MMR genes are downregulated or functionally impaired, adequate repair of DNA replication errors is impossible, leading to a greater occurrence of somatic alterations.[20] Our investigation performed an additional evaluation of the connection among the differential expression levels of WDR43 and 5 distinct MMR genes (MSH2, MSH6, PMS2, MLH1, and EPCAM) in 33 forms of cancer.