title: Minimally differentiated acute myeloid leukemia (AML-M0): a distinct clinico-biologic entity with poor prognosis.
abstract: FAB proposals for the diagnosis of AML-M0 represent the formal recognition of a distinct entity which has been described over the past few years by several authors and called minimally differentiated acute myeloid leukemia. By definition, AML-M0 includes acute leukemias which do not fit morphological and cytochemical criteria for the diagnosis of AML, and for which myeloid lineage assignment can be made by immunological assay showing positivity for MPO, CD13, and CD33 and negativity for lymphoid markers. Involvement of an early myeloid progenitor in the leukemic process is a possible theory hypothesized to explain the existence of such a form. Validity of this assumption has been based on the observation that AML-M0 frequently bears "stem cell" markers such as CD34, HLA-DR, Tdt, CD7, and promiscuous IgH/TCR gene rearrangements, which are thought to occur in uncommitted cells. Finally, AML-M0 very frequently carries cytogenetic abnormalities common to MDS or secondary AML, such as -5/5q- or -7/7q- deletions and or complex karyotype. In our experience, AML-M0 is also very often associated with the MDR phenotype, which in turn has been found strictly linked to "stem cell" features, especially in MDS. These biological aspects, altogether, translate into a very unfavorable prognosis, confirming even from a clinical point of view that AML-M0 is a distinct entity. In conclusion, "stem cell" markers, MDR phenotype, complex chromosome lesions, frequent occurrence in elderly patients, and intrinsic chemoresistance characterize AML-M0 and indicate the need for tailored treatments, possibly involving the use of MDR modulators and/or differentiating agents.
authors.affiliation: Chair of Hematology, University of Rome Tor Vergata, Ospedale S. Eugenio, Roma, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Amadori
authors.forename: A
authors.initials: A
authors.lastname: Venditti
authors.forename: G
authors.initials: G
authors.lastname: Del Poeta
authors.forename: R
authors.initials: R
authors.lastname: Stasi
authors.forename: F
authors.initials: F
authors.lastname: Buccisano
authors.forename: A
authors.initials: A
authors.lastname: Bruno
authors.forename: A
authors.initials: A
authors.lastname: Tamburini
authors.forename: M C
authors.initials: MC
authors.lastname: Cox
authors.forename: L
authors.initials: L
authors.lastname: Maffei
authors.forename: G
authors.initials: G
authors.lastname: Aronica
authors.forename: M D
authors.initials: MD
authors.lastname: Simone
authors.forename: G
authors.initials: G
authors.lastname: Adorno
authors.forename: M
authors.initials: M
authors.lastname: Masi
authors.forename: M
authors.initials: M
authors.lastname: Tribalto
authors.forename: G
authors.initials: G
authors.lastname: Papa
mesh_terms: D006801:Humans; D016130:Immunophenotyping; D015470:Leukemia, Myeloid, Acute / Q000276:immunology / Q000473:pathology / Q000503:physiopathology*; D011379:Prognosis