MPN Acronyms - abbreviations and some commonly used terms in discussion of Myeloproliferative Neoplasms


Drugs that chemically modify DNA cells to destroy them by adding alkyl groups. Agents include busulfan, pipobroman and chlorambucil.


Acute Lymphocytic Leukemia � excess of lymphoblasts, most common type of cancer in children, cure rate in them is 80% and adults up to 60%.


Acute Myeloid Leukemia � most common type of acute leukemia; phases are measured by levels of abnormal immature white cells (blasts): chronic phase- < 10% blasts, accelerated phase 10-19% blasts, blast phase 20+% blasts; blast crisis � 20% blasts with fever, fatigue and enlarged spleen.


Agnogenic Myeloid Metaplasia or Chronic Idiopathic Myelofibrosis � obsolete term; now usually called primary myelofibrosis � see MF, IMF, PMF.


Philadelphia Chromosome translocation (see Ph) to form the oncogene which causes CML.


Agent used to prevent clotting � old standard is warfarin, a vitamin K antagonist, requiring frequent monitoring and sensitive to diet and drug interactions. New drugs include Pradaxa dabigatran, Eliquis apixaban and Xarelto rivaroxaban. These are thrombin factor IIa or Xa inhibitors so diet and drug interactions are minimal and monitoring is not required. They are more robust stroke preventers than warfarin and reduce intracranial bleeding.


Bone Marrow Biopsy � removal of aspirate and solid tissue from marrow for analysis. Can be done under local anesthetic, or with "conscious sedation" to ensure a minimum of discomfort from the procedure.


Bone Marrow Transplant, the only cure for an MPN, but is expensive and comes with high risk. ABMT � autologous bone marrow transplant � your own marrow. Generally not used in MPNs. BMT � allogeneic bone marrow transplant � someone else's marrow MUD-bone marrow transplant � marrow from matched unrelated donor SBMT-syngeneic bone marrow transplant � identical twin's marrow PBPC � peripheral blood progenitor cell transplant PBSCT � peripheral blood stem cell transplant PBSCR � peripheral blood stem cell rescue PSCT or PSCR � same as above without the word "blood."


Complete Blood Count � called Full Blood Count (FBC) in some countries. See Hct, Hg or Hgb, MCH, MCHC, MCV, PT/PL, RBC, RDW, WBC, WCC.


Cluster of Differentiation � system of classifying lymphocytes according to antigen collections on their cell surfaces, also called CD markers, eg � rituximab destroys B cells that have CD20 antigen on their surface.


Chronic Myelogenous Leukemia � also called chronic myeloid leukemia; the Philadelphia chromosome is present in 90+% of patients with high white cell counts (up to 100 to 300), and in those where it isn't present, the BCR-ABL fusion gene is generally identifiable. Since granulocytes are involved in this type of leukemia, it is also referred to as CGL or chronic granulocytic leukemia.


Deoxyribonucleic Acid � the cell nucleus material that contains genetic instructions.


Erythropoietin � a hormone controlling red cell production; it promotes RBC survival by protecting from apoptosis (programmed suicide cell death).


Erythrocyte cell count (see RBC).


Essential Thrombocythemia/thrombocytosis � MPN variant where platelet count is over 400.




Fluorescence In Situ Hybridization � an analytical technique: a fluorescent probe that detects DNA sequences in situ (in normal position within a chromosome) and thereby detects abnormalities.


Graft-Versus-Host Disease � complication of allogeneic BMT in which immune cells in the transplanted marrow treat the recipient's tissues (the patient's) as foreign and cause an immunologic attack.


Hemoglobin � oxygen carrying component in red blood cells. Labs report the concentration in grams of hemoglobin in one liter of blood although some report it in 100 milliliters (one deciliter). Normal female 12-16 g/deciliter, male 14-18 g/deciliter (ie 120-160, and 140-180 g/l) (see RBC).


Hematocrit � the percentage by volume of whole blood that consists of blood cells (the remainder is plasma). Measured in a centrifuged test tube; also called PCV � packed cell volume or EVF-erythrocyte volume fraction; reference range for females is approximately 33-43; for males 40-53; quoted as a decimal number by some laboraties (ie 0.40-0.53).


and HLA typing and matching � Human leukocyte antigen (HLA) typing is used to match patients and donors for allogeneic bone marrow transplants. HLA are proteins � or markers � found on most cells in your body. A close match between your HLA markers and your donor's can reduce the risk that your immune cells will attack your donor's cells or that your donor's immune cells will attack your body after the transplant. If you need an allogeneic transplant (which uses cells from a family member, unrelated donor or cord blood unit), your doctor will take a blood sample to test for your HLA type. (Acknowledgement � from


Hemorrhagic Thrombocythemia � term applied to ET with bleeding episodes.


Hydroxyurea (hydroxycarbamide) � oral chemotherapeutic agent used to treat elevated blood counts in MPNs. It has a low incidence of secondary leukemias and cancers compared to P32 and alkylating agents, and has been the gold standard treatment for MPNs until the advent of Interferon in its various forms.


Idiopathic myelofibrosis; see PMF


Interferon � a protein produced by the body when exposed to a virus; recombinant alpha-interferon forms are used in MPNs. Can produce lasting remissions and allow patients treatment-free periods. Roferon and Intron A are the main brand options, Peg-Intron and Pegasys are sustained release forms now more commonly used. All forms of Interferon are administered via subcutaneous injection.


International Normalized Ratio � test measuring time it takes blood to clot compare to an average; target range for warfarin dosing 2.0-3.0.


Genetic mutation found in majority of MPN patients: PV>95%, ET & PMF around 50%.


Janus Kinase-Signal Transducer & Activator of Transcription � a signal transduction pathway, ie the molecular-level messaging that occurs within cells; STATs are phosphorylated by JAKs, go into cell nuclei, bind to specific elements and induce gene transcription.


Enzymes also called phosphotransferases � they transfer phosphate groups to proteins which then act as on-off switches in many biochemical systems.


Leukocyte count � number of white cells in a given volume of blood.


International Normalized Ratio � test measuring time it takes blood to clot compare to an average; target range for warfarin dosing 2.0-3.0.


generic name suffix indicating drug is a Monoclonal AntiBody; e.g. rituximab.


Mean Cell Hemoglobin � Average weight of hemoglobin in the red blood cell; normal 27-33 pg (picograms).


Mean cell hemoglobin concentration � % of average red cell which is filled with hemoglobin; normal 33.1-35.6.


Mean Cell Volume � average size of the red cells. MCV tends to be low if treated by phlebomoties, as iron deficiency, the goal of phlebotomies, causes red cells to be of smaller average size; normal range 80-100 fL (femtoliters, or 1x10 to minus 15th power of a liter).


Myelodysplastic Syndrome � previously "preleukemia", or "smouldering leukemia"; a diverse collection of conditions involving ineffective production (dysplasia) of the myeloid class of blood cells; closely related to, but different from, MPNs.


Myelofibrosis � replacement of normal marrow with useless fibrous tissue. See PMF, sMF.


Myelofibrosis with Myeloid Metaplasia � MF with involvement of other organs � spleen and liver most commonly become the sites of blood-producing cells, in an attempt to compensate for reduced bone marrow effectiveness due to fibrosis.


Myeloproliferative diseases; now called Myeloproliferative neoplasms MPNs.


Myeloproliferative Neoplasms � chronic bone marrow cancers (leukemias): ET, MF, PV(all without the Philadelphia Chromosome � ie Ph negative), CML (Philadelphia Chromosome positive, Ph +ve), mast cell disorders, systemic mastocytosis. MPDs were renamed "neoplasms" in 2008, after a review and reclassification of myeloid malignancies.


Generic name suffix indicating drug is an antineoplastic; eg. Ruxolitinib.


Radioactive Phosphorus � injectable therapy to suppress high blood counts; mainly used in the elderly, as a higher rate of leukemia can occur.


Pegylated Interferon alfa-2b � polyethylene glycol sustained release form (see IFN).


Pegylated Interferon alfa-2a � polyethylene glycol sustained release form; fewer side effects than non-pegylated (normal) Interferon (see IFN).


Philadelphia Chromosome � abnormality associated with CML (sometimes ALL) caused by translocation between chromosomes 9 and 22; see BCR-ABL.


Primary (or idiopathic) myelofibrosis. One of the three main non-Philadelphia chromosome MPNs (with ET and PV).


Postpolycythemic Myelofibrosis with Myeloid Metaplasia; commonly referred to as secondary MF � see sMF.


Platelet count � the number of platelets in a given volume of blood. Either quoted as per liter (eg, reference range of 150-400 x 109 per liter) or per microliter (reference range of 150,000-400,000).


Prothrombin Time � measures time for blood to clot after addition of tissue factor.


Polycythemia Vera (Polycythemia Rubra Vera) � MPN variant with increased hematocrit, red cell count, increased blood volume and viscosity; white cells and platelets can also be raised.


Red Blood Cell count � Normal female 3.9-5.2; male 4.2-5.6 (both number of cells, times 10 to the 12th, per liter).


Red Cell Mass test for volume/mass of circulating red blood cells used to confirm diagnosis of PV; normal males 24-32 mL/kg, females 21-27. Rarely used now as JAK2 and EPO tests generally preferred.


Red Cell Volume Distribution Width � degree to which red cells vary in size from one another; normal 10.9-13.7 (Mayo Clinic).


restless leg syndrome. Commonly associated with iron deficiency in MPNs.


Stem Cell Transplant � a BMT in which stem cells from the peripheral blood are used.


Myelofibrosis occurring as a progression from another of the MPNs, generally following PV, ET, or CML.


Secondary Polycythemia � high hemoglobin and hematocrit. Can be caused by smoking, high altitude, chronic heart, lung or kidney disease; resolves when cause removed, or underlying disease is treated. Driven by an increase in the cytokine EPO, produced by the kidneys when oxygen levels are chronically low.


Total Iron Binding Capacity � test of blood's capacity to bind iron to transferrin; normal 240-450 micrograms/deciliter.


Thrombopoietin � hormone that regulates megakaryocyte (platelet precursors) production, and thus platelets; it operates through its receptor (Mpl) to stimulate production.


von Willebrand Disease � bleeding disorder caused by deficiency of VWFactor which helps platelets clump and stick to blood vessel walls; usually hereditary but Acquired VWD may occur in ET due to sequestration of Factor by adhesion to the high number of platelets.


White Blood Cell Count � normal range 4-11x109 per liter (ie 4-11 billion cells per liter, sometimes quoted as 4000-11,000 per microliter). The precise range varies slightly between laboratories and regions.



Compiled by R Niblack,G Gjerde and I Sweet. Enquiries and comments should be sent to