The MDM2-p53 autoregulatory loop is a central regulator of cellular stress responses, and in myeloid neoplasms-including acute myeloid leukemia (AML) and myeloproliferative neoplasms (MPN)-p53 is frequently retained but functionally suppressed through MDM2 overexpression and oncogenic signaling, notably via JAK-STAT activation. The gene discussed is TP53; the disease is myeloproliferative neoplasm.