This phenomenon is particularly relevant in colorectal cancer (CRC), where MSI is detected in approximately 15–20% of cases, predominantly as a result of sporadic hypermethylation of the MLH1 promoter or associated with Lynch syndrome due to germline mutations in MMR genes such as MLH1, MSH2, MSH6, and PMS [27,28]. The gene discussed is MSH2; the disease is colorectal cancer.