In the present study, we had the opportunity to investigate ATRX in 2 patients with corticotroph tumors, 1 nonaggressive macroadenoma and 1 carcinoma, and Lynch syndrome, a cancer predisposing syndrome with mutations in genes involved in DNA mismatch repair (MLH1, MSH2, MSH6, PMS2, EPCAM). The gene discussed is MLH1; the disease is Lynch syndrome.