Lujambio et al. analyzed the miRNA expression profile of a colon cancer cell line, which was genetically deficient for the DNA methyltransferase (DNMT) enzymes DNMT1 and DNMT3b, and identified the epigenetic silencing of mir-124a in various types of cancer, including colon, breast, and lung cancers as well as leukemia and lymphoma. The gene discussed is DNMT1; the disease is cancer.