Another report, based on analyses of the mutation and promoter methylation status of the MSH2 and MLH1 genes in unpaired diagnostic, relapsed, and refractory samples from 53 pediatric and adult patients with AML, suggested that aberrations affecting mismatch repair genes were significantly more frequent in refractory/relapsed samples than in diagnostic ones (12/25 versus 6/28) [118]. The gene discussed is MLH1; the disease is acute myeloid leukemia.