Various researchers are interested in the influence of cfDNA in conquering the tumor mutational burden from two CRC MMR-D subjects, which clarified the feasibility of cfDNA as a substitute marker for MMR-D and the five quasimonomorphic MSI markers BAT-25, BAT-26, NR21, NR24, as well as NR27, and four MMR genes (MSH2, MSH6, PMS2, and MLH1). This evidence concerns the gene MLH1 and colorectal carcinoma.