Glossary

Helpful Terms to Know

Acquired Von Willebrand’s Syndrome a rare disorder where the platelets interfere with the body’s normal clotting mechanism and there is abnormal bleeding. 

Acute Myeloid Leukemia (AML) is a fast-growing blood cancer in which the bone marrow produces large numbers of immature white blood cells called blasts. These abnormal cells crowd out healthy blood cells, leading to symptoms such as fatigue, infections, easy bruising, and bleeding. AML typically develops on its own but can also arise from earlier blood conditions like myelodysplastic syndromes or myeloproliferative neoplasms (MPNs). 

Allele One member of a pair or series of genes that occupy a specific position on a specific chromosome. The MPN community discusses “allele burden” as a metric that may or may not be related to disease progression. 

Allogenic Stem Cell Transplant A procedure in which a person receives blood-forming stem cells (cells from which all blood cells develop) from a genetically similar, but not identical, donor. This is often a sister or brother but could be an unrelated donor. 

Anemia When the number of red blood cells is below normal, it can result in fatigue, weakness, and shortness of breath. 

Apoptosis The process of programmed cell death (PCD) that may occur in multicellular organisms. 

Aurora Kinase Enzymes essential to cell proliferation. The enzyme helps the dividing cell dispense its genetic materials to its daughter cells. 

Aurora Kinase Inhibitors Substance which blocks enzymes (Aurora kinases) involved in cell division and may kill cancer cells. 

Autologous Stem Cell Transplant A transplant in which a patient’s own blood-forming stem cells are collected. He or she is then treated with high doses of chemotherapy, or a combination of chemotherapy and radiation. The high-dose treatment kills cancer cells, but also eliminates the blood-producing cells that are left in the bone marrow. 

Biomarkers are biological molecules found in blood, other body fluids, or tissues that are a sign of a normal or abnormal process, or of a condition or disease. A biomarker may be used to see how well the body responds to a treatment for a disease or condition. Also called a molecular marker or signature molecule. 

Biomarker Testing is a laboratory method that uses a sample of tissue, blood, or other body fluid to check for the presence or changes in certain genes, proteins, or other molecules that may be a sign of a disease or condition, such as cancer. It may also be used to help plan treatment, find out how well treatment is working, make a prognosis, or predict whether cancer will come back or spread to other parts of the body. Also referred to as molecular profiling or molecular testing. 

Blasts Undeveloped, immature blood cells that develop in the bone marrow before entering the blood stream as mature blood cells. In MPNs, blasts can sometimes be found in the blood stream. 

Bone Marrow Biopsy A procedure used to remove soft tissue, called marrow, from inside the bone. A reading of a Bone Marrow Biopsy to detect the amount of fibrosis in the bone marrow is often used in part to diagnose myelofibrosis. 

CALR Mutation (Calreticulin mutation) The CALR gene is the second most frequent somatic mutation after JAK2 in ET and pMF patients. It is not found in people with PV. CALR mutations are mutually exclusive of JAK2 and MPL mutations. In ET and MF, CALR mutations have a frequency of approximately 49% to 88%. 

Chimeric Antigen Receptor (CART) Cells  Cells taken from a patient’sbody and programed to identify and kill cancer cells when returned to the patient’s blood stream. 

CAR T – Cell Therapy The process of harvesting cells from blood or bone marrow, which are genetically modified before being expanded in number. This modification targets the T cells specifically to the patient’s cancer and triggers them to attack when returned to the patient’s body. 

Chemokines Any of various chemical signals called cytokines produced in acute and chronic inflammation that mobilize and activate white blood cells. 

Compendia In the pharmaceutical industry, a compendium is a comprehensive listing of drugs. It typically includes a summary of the pharmacologic characteristics of each listed drug or biological; information on dosage; and, often, recommended uses for specific diseases. The current recognized compendia for off-label cancer drugs are: American Hospital Formulary Service Drug Information (AHFS-DI), National Comprehensive Cancer Network (NCCN) Drugs and Biologics, Clinical Pharmacology, and Thompson Reuters- DrugDex.  

Complete Blood Count (CBC) A blood test used to evaluate your overall health and detect a wide range of disorders. Used in diagnosing someone with ET, PV, and MF among other conditions. A complete blood count test measures several components and features of your blood, including: red blood cells, which carry oxygen. 

CRISPR-Cas9 Gene Editing A laboratory method which has potential application for genetic editing of humans, animals, and other organisms. By delivering the Cas9 protein and appropriate directions, in the form of RNAs, into a cell, the organism’s genome can be cut and edited at desired locations. 

Cytokine A type of protein or molecule that has an effect on the immune system. Some cytokines stimulate the immune system and others slow it down. Cytokines are often produced by immune cells but can also be produced by nonimmune cells. They can also be made in the laboratory and used therapeutically. 

Cytopenias A deficiency of some cellular element in the blood of an individual. 

Cytoplasm The space outside the nucleus of a cell, usually containing various cellular structures. 

Cytoreductive Reducing the number of cells. 

Data Linkage is the process of securely combining a person’s health information from different sources, such as electronic medical records, laboratory results, and health surveys. Linking these different types of data helps researchers build a more complete and accurate picture of a person’s health and how their condition changes over time. 

DNA Sequencing The term DNA sequencing refers to laboratory methods for determining the order of the nucleotide bases — adenine, guanine, cytosine, and thymine — in a strand of DNA. DNA sequencing can identify the presence of gene mutations. 

Electronic Health Record (EHR) is a digital record of a patient’s medical information that allows authorized healthcare providers across different care settings to access and share information. EHRs include data such as diagnoses, medications, laboratory and imaging results, immunizations, treatment plans, and visit summaries from multiple clinicians involved in a patient’s care. EHRs provide healthcare providers with a comprehensive view of a patient’s health history, which improves the coordination of care. 

Electronic Medical Record (EMR) is a digital record of a patient’s medical information over time. They are used by individual doctors’ offices, clinics, and hospitals to support care. These records contain medical information such as diagnoses, medications, test results, vital signs, treatment plans, imaging reports, and visit notes, as well as administrative details like demographics and immunization history. EMRs help healthcare providers within one practice or institution track a patient’s condition, reduce medical errors, and improve care at that location. 

Endogenous Produced or growing from within. 

Endosteal The thin layer of cells lining the medullary cavity of a bone. 

Endothelial A thin layer of flat epithelial cells that lines serous cavities, lymph vessels, and blood vessels. 

Endpoint in clinical trials is an event or outcome measured in the participants and used to determine whether a treatment is safe and effective. The endpoints of a clinical trial are usually included in the study objectives. Some examples of endpoints are patient survival, improvements in quality of life, relief of symptoms, and disappearance of the tumor. 

Erythropoietin A hormone that stimulates production of red blood cells and hemoglobin in the bone marrow. 

Essential Thrombocythemia (ET) is a long-lasting myeloproliferative neoplasm (MPN) characterized by an increased number of platelets in the blood. ET may be driven by mutations in genes such as JAK2, CALR, or MPL. Most commonly diagnosed in women over the age of 50, ET is associated with the overproduction of platelet precursors in the bone marrow and complications frequently include blood clots and/or bleeding. 

Extramedullary Hematopoiesis Blood production that occurs outside the bone marrow, in the spleen, liver, or lymph nodes. This is the primary cause of enlarged spleens in MPN patients. 

Fast Healthcare Interoperability Resources (FHIR) is a modern technology standard that allows different health systems and apps to securely share medical information in a common, consistent format. FHIR makes it easier for electronic medical records (EMRs) to exchange information, even if they store or organize patient data differently.  

Fibrocytes A cell that produces fibrous tissue; also called fibroblast. 

Fibrosis the buildup of scar-like tissue in the bone marrow which makes it harder for the body to produce healthy blood cells.  

Hematopoietic or Haemopoietic Related to the formation of blood or blood cells. Hematopoietic is often use to describe stem cells in the bone marrow which produce mature blood cells (hematopoietic stem cell). 

Haplotype A set of alleles of different genes that are closely linked on one chromosome and are usually inherited as a unit. 

Hematopoietic Stem Cells (HSCs) Stem cells that give rise to all the blood cell types including myeloid (monocytes and macrophages, neutrophils, basophils, eosinophils, erythrocytes, megakaryocytes/platelets, dendritic cells), and lymphoid lineages (T-cells, B-cells, NK-cells). 

Hemoglobin a molecule inside of the red blood cells that carries oxygen. 

Hepatomegaly Enlargement of the liver. 

Homozygous A cell is said to be homozygous for a particular gene when it carries identical alleles of the gene on both homologous chromosomes. The cell or organism in question is called a homozygote. 

Honest Broker is a person who helps protect your privacy when participating in a research project. Their job is to keep your personal information (like your name or date of birth) separate from the health data that researchers use. 

Informed Consent is the process by which a person voluntarily agrees to take part in a research study after receiving clear, complete, and understandable information about what participation involves. This includes learning about the purpose of the study, what data will be collected, any potential risks or benefits, and the person’s right to say no or to withdraw at any time. Informed consent ensures that participants fully understand how their medical data will be used and that their choice to share it is entirely voluntary. 

Institutional Review Board (IRB) is an independent committee of experts that reviews and oversees medical research involving people to ensure it is ethical and protects participants’ rights and safety. Before and throughout a research study, the IRB reviews the research plan, including how participants will be informed and treated. All U.S.-based research involving patients must be approved by an IRB to ensure participants are treated fairly, respectfully, and with full transparency. 

Idiopathic Relating to or being a disease with no known cause. 

Immunotherapy A type of cancer treatment that uses the body’s own immune system to find and fight cancer. It works by either stimulating the immune system to work harder or by adding man-made components, such as laboratory-produced antibodies, to help attack cancer cells more effectively. Some immunotherapies target specific proteins on cancer cells to block their growth or help the immune system recognize them. These are sometimes referred to as targeted therapies, though not all targeted therapies are immunotherapies. 

JAK2V617F The genetic mutation found in approximately 50% of essential thrombocythemia, 95% of polycythemia vera, and 50% of myelofibrosis patients. This mutation interferes with the function of the JAK2 protein, causing it to be continuously activated. 

JAK2 Inhibitors A class of drugs which was developed with the purpose of targeting the over active JAK2 proteins present because of a mutation to the JAK2 gene. The first approved by the FDA was Jakafi (Jakavi in Europe) by Incyte.  

Knock-In Mouse Model A group of mice that have been genetically engineered by scientists to possess an extra or working copy of a gene of interest to allow for laboratory research. Mouse models are common in scientific research due to the high degree genetic similarity between mice and humans. 

Legally Authorized Representative (LAR) is a person who is legally allowed to give consent for someone else to join a research study when that person cannot make the decision for themselves. This may happen if an adult has a medical condition that affects their ability to understand or communicate clearly. Depending on state law, an LAR might be a spouse, adult child, parent, legal guardian, or another individual authorized by the courts or by regulations. LARs are only used when a participant is unable to make an informed decision and must always act in the best interest of that person. 

Leukemogenesis The process, development, and progression of cancerous leukemic cells or a leukemic disease. 

Lymphoid Part of or relating to lymph or the lymphatic tissue where the type of white blood cells called lymphocytes are formed 

Macrophage A large white blood cell, occurring principally in connective tissue and in the bloodstream, that ingests foreign particles and infectious microorganisms by phagocytosis. 

Megakaryocyte A bone marrow cell responsible for the production of blood thrombocytes (platelets), which are necessary for normal blood clotting. Megakaryocytes normally account for 1 out of 10,000 bone marrow cells but can increase in number nearly 10-fold in certain diseases. 

Monoclonal antibodies An immune system protein that can be produced in laboratories. Antibodies can be very useful in treating cancer because they can be designed to attack a very specific part of a cancer cell. 

Monocyte A type of white blood cell and is part of the human body’s immune system. Monocytes play multiple roles in immune function, including replenishing resident macrophages and dendritic cells  

MPL Mutation A mutation to a gene which helps control how the body makes platelets which is present in patients with MF and ET at a frequency of approximately 5% and 1%, respectively. 

Myelodysplastic Syndrome (MDS) is a group of blood cancers characterized by poorly functioning bone marrow stem cells that do not produce enough fully developed or healthy red blood cells, white blood cells, or platelets. This leads to symptoms like fatigue, frequent infections, and easy bruising or bleeding. Although it is not classified as an MPN, MDS can sometimes overlap with MPNs and may evolve into acute myeloid leukemia (AML). The condition is often diagnosed through a combination of blood tests, bone marrow biopsies, and genetic analysis to identify clonal mutations or chromosomal abnormalities. 

Myelofibrosis (MF) is a long-lasting myeloproliferative neoplasm (MPN) where abnormal blood-making stem cells in the bone marrow cause scarring (fibrosis) and ongoing inflammation. This disrupts normal blood cell production and may cause the spleen or other organs to take over blood formation, often leading to spleen enlargement. 

Myeloproliferative Neoplasms (MPNs) are a group of rare, chronic blood cancers that begin in the bone marrow, where blood cells are made. The three classic types of MPNs are essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF). In these MPNs, genetic mutations in blood-forming stem cells cause the body to produce too many mature red cells or platelets. This can lead to symptoms and complications like fatigue, itchiness, anemia, bleeding or clotting problems, bone fibrosis, or an enlarged spleen. 

Myeloproliferative Neoplasm in Accelerated Phase (MPN-AP) is when an MPN has reached an advanced stage where immature blood cells, called blasts, make up 10% to 19% of the cells in the bone marrow or circulating blood. This phase signals disease progression and may include worsening symptoms such as anemia, low platelet counts, or increased spleen size. Patients with MPN-AP are at high risk of progressing to blast phase, and clinicians may suggest more intensive treatments or stem cell transplants. 

Myeloproliferative Neoplasm in Blast Phase (MPN-BP) is the most advanced and aggressive stage of an MPN, defined by the presence of 20% or more blasts (immature blood cells) in the bone marrow or circulating blood. It is considered a type of acute myeloid leukemia and is typically associated with severe symptoms, low blood counts, and a poor prognosis. Treatment options may include chemotherapy, hypomethylating agents, targeted therapies, or stem cell transplant, depending on the patient’s health and genetic profile. 

Myeloproliferative Neoplasm, Unclassifiable (MPN-U) or sometimes called myeloproliferative neoplasm, not otherwise specified (MPN-NOS) is a diagnosis given when a person clearly shows signs of a myeloproliferative neoplasm but doesn’t meet the full criteria for any specific MPN like essential thrombocythemia, polycythemia vera, or myelofibrosis. This may happen when the disease is in an early stage, when it has progressed to a more advanced or fibrotic form, or when another illness makes diagnosis more difficult. MPN-U can vary widely in how it appears and changes over time, and treatment is often tailored to the patient’s symptoms and clinical needs. 

Morphogenesis The constellation of biological processes that determine an organism’s shape, which is inextricably intertwined with cell growth and differentiation, the other key elements of developmental biology. 

Neoplastic Relating to or constituting a condition involving abnormal new growth of tissue, like a tumor or neoplasia. 

Neutropenia A significant decrease in the number of white blood cells. 

Non-specific immunotherapies These treatments boost the immune system in a general way, may help the immune system attack cancer cells. 

Notch Signaling The notch signaling pathway is a highly conserved cell signaling system present in most multicellular organisms. 

Oncogenic Having the potential to cause cancer or tumor.  

Osteoblastic A bone-forming cell. 

Osteosclerosis An elevation in bone density that can occur in people with an MPN. It is normally detected on an X-ray as an area of whiteness indicating where the bone density has significantly increased. 

Overall Survival (OS) is the length of time from either the date of disease diagnosis or the start of treatment that a patient is still alive. In a clinical trial, measuring OS is one way to see how well a new treatment works. 

Patient Reported Outcome (PRO) is information about a patient’s health that comes directly from the patient. Examples of PROs include a patient’s description of their symptoms, their satisfaction with care, and how a disease or treatment affects their physical, mental, emotional, and social well-being. In clinical trials, PROs may provide information about the side effects of the new treatment being studied. The use of patient-reported outcomes may help plan the best treatment and improve quality of care. 

Paracrine signaling A form of cell-to-cell communication in which a cell produces a signal to induce changes in nearby cells, altering the behavior or differentiation of those cells. Signaling molecules known as paracrine factors diffuse over a relatively short distance (local action), as opposed to endocrine factors (hormones which travel considerably longer distances via the circulatory system). Cells that produce paracrine factors secrete them into the immediate extracellular environment. 

PD-1 Inhibitors A type of drug or treatment which effects the programmed cell death pathway connected to the PD-1 receptor on cells. PD-1 inhibitors prevent the activation of T-cells, which reduces the body’s ability to protect itself with its immune system.  A new class of cancer drugs that block PD-1, the PD-1 inhibitors, activate the immune system to attack tumors to varying degrees of success. 

Pegasys (Pegylated interferon alfa-2a) An antiviral drug discovered at the pharmaceutical company F. Hoffmann-La Roche; it has a dual mode of action: antiviral and immune system. The addition of polyethylene glycol to the interferon, through a process known as pegylation, enhances the half-life of the interferon when compared to its native form. 

Petechiae Flat, red, pinpoint spots under the skin caused by bleeding. 

Phagocytosis The process by which a cell, such as a white blood cell, ingests microorganisms, other cells, and foreign particles. 

Phenotype Any observable characteristic or trait of an organism: such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior (such as a bird’s nest). 

Phlebotomy The act or practice of opening a vein by incision or puncture to remove blood as a therapeutic treatment. Also called venesection. 

Phosphorylation The addition of phosphate group to an organic compound through the action of a phosphorylase or kinase. 

Pluripotency Pluripotent means many. A pluripotent cell can create all cell types except for extra embryonic tissue, unlike a totipotent cell, meaning all, which can produce every cell type including extra embryonic tissue. 

Polycythemia Vera (PV) is a long-lasting, progressive myeloproliferative neoplasm (MPN) characterized by high amounts of red blood cells. PV may be driven by mutations in genes such as JAK2, CALR, or MPL. The disease is most common in men over the age of 60, but anyone can develop PV. PV patients typically experience an elevated leukocyte (white blood cell) count, an elevated platelet count, and an enlarged spleen. 

Pre-fibrotic Primary Myelofibrosis (pre-pMF) is an early stage of the rare, chronic blood cancer primary myelofibrosis (pMF), classified as a myeloproliferative neoplasm (MPN). It is marked by the abnormal growth and development of platelet-producing cells (called megakaryocytes) in the bone marrow. These changes may be driven by mutations in genes such as JAK2, CALR, or MPL. Unlike overt PMF, pre-PMF has little to no marrow scarring (fibrosis) at diagnosis, though fibrosis can develop over time. Some people with pre-pMF report fatigue, night sweats, or spleen enlargement, and are at an increased risk of blood clots. 

Primary Myelofibrosis (pMF) is a rare, chronic myeloproliferative neoplasm (MPN) characterized by the overproduction of blood-making cells in the bone marrow. It is often related to mutations in genes such as JAK2, CALR, or MPL. Over time, the marrow becomes scarred (fibrotic), leading to anemia, an enlarged spleen, and other symptoms that affect quality of life. Unlike secondary myelofibrosis, which occurs after other MPNs such as essential thrombocythemia or polycythemia vera, pMF arises on its own (de novo). Although its origin differs, the clinical presentation and treatment approach to primary myelofibrosis is generally like that of secondary myelofibrosis (sMF). 

Principal Investigator (PI) is the lead researcher responsible for the overall design, conduct, and oversight of a clinical study or research project. Their responsibilities include ensuring ethical standards, regulatory compliance, data integrity, and participant safety throughout the course of a study. 

Progression (Disease Progression) refers to the worsening or advancement of a disease over time, often marked by new symptoms, changes in laboratory results, or the spread of disease to other parts of the body. In myeloproliferative neoplasms (MPNs), progression can include a shift from one phase or disease state to another — such as the development of overt myelofibrosis or acute myeloid leukemia. Signs of progression in MPNs include changes in or increased symptoms like anemia, bone fibrosis, enlarged spleen, or blood clotting or bleeding problems. 

Progression-Free Survival (PFS) is the length of time during and after the treatment of a disease, such as cancer, that a patient lives with the disease, but it does not get worse. In a clinical trial, measuring progression-free survival is one way to see how well a new treatment works. 

Proteomics The branch of biochemistry concerned with the structure and analysis of the proteins occurring in living organisms. 

Pruritus Severe itching. A common symptom of people with MPN. 

Real World Evidence (RWE) is information obtained from doctor’s offices or clinics about how diseases progress and treatments perform, based on data gathered during routine patient care. RWE can reveal how patients respond to treatments over time, how symptoms progress, and how care is delivered within or outside of clinical trials. 

Secondary Myelofibrosis (sMF) is a progressive form of myelofibrosis that develops from other myeloproliferative neoplasms (MPNs), specifically essential thrombocythemia (post-ET MF) or polycythemia vera (post-PV MF). Like primary myelofibrosis, sMF is marked by bone marrow scarring, anemia, spleen enlargement, and symptoms such as fatigue, night sweats, and weight loss. Although its origin differs, the clinical presentation and treatment approach is a lot like those of primary myelofibrosis. 

Secondary Acute Myeloid Leukemia (sAML) is when AML develops in people who already have another blood disorder, such as myeloproliferative neoplasm (MPN) or myelodysplastic syndrome. Secondary AML can be harder to treat than other types of AML and have a poorer prognosis. In people who had MPNs, secondary AML typically occurs after the disease has worsened, progressing through more advanced stages such as blast phase. (See the definition for Acute Myeloid Leukemia and Myeloproliferative Neoplasm in Blast Phase) 

Splenomegaly Enlargement of the spleen. A common symptom for MPN patients, which occurs once blood production begins taking place in the spleen. Patients will sometimes undergo a splenectomy to remove the spleen, and reduction in spleen is an outcome of several MPN drugs. 

Stem Cells Biological cells found in all multicellular organisms, that can divide (through mitosis) and differentiate into diverse specialized cell types and can self-renew to produce more stem cells. In mammals, there are two broad types of stem cells: embryonic stem cells, which are isolated from the inner cell mass of blastocysts, and adult stem cells, which are found in various tissues. In adult organisms, stem cells and progenitor cells act as a repair system for the body, replenishing adult tissues. 

Stem Cell Transplant is a medical procedure that replaces the cells of diseased or damaged bone marrow with healthy blood-forming stem cells, usually from a donor. It may be considered for people with advanced myeloproliferative neoplasms (MPNs), such as myelofibrosis or MPN in blast phase. Although it offers the possibility of long-term remission, it also carries serious risks, and not all patients are eligible for this treatment. 

Stroke Rapid loss of brain function due to a disturbance of blood flow to the brain such as a blockage or hemorrhage. 

Stromal cells  Cells of an organ that form loose connective tissue. These are the cells that make up the support structure of biological tissues and support the parenchymal cells. The interaction between stromal cells and tumor cells is known to play a major role in cancer growth and progression. In addition, by regulating local cytokine networks, bone marrow stromal cells have been described to be involved in human hematopoiesis and inflammatory processes. 

Recombinant Material produced by genetic engineering. 

Thrombocytopenia An abnormal decrease in the number of platelets in circulatory blood. 

Thrombocytosis When the body produces a surplus of platelets (thrombocytes). 

Thrombopoietin (TPO)  A hormone produced mainly by the liver and the kidney that regulates the production of platelets by the bone marrow. It stimulates the production and differentiation of megakaryocytes, the bone marrow cells that fragment into large numbers of platelets. 

Transient Ischemic Attack (TIA)  A temporary blockage of the blood supply to the brain caused by a blood clot and usually lasting 10 minutes or less, during which dizziness, blurring of vision, numbness on one side of the body, and other symptoms of a stroke may occur. Also called ministroke. 

Wernicke’s Encephalopathy A neurological disorder caused by thiamine deficiency, typically from chronic alcoholism or persistent vomiting, and marked by mental confusion, abnormal eye movements, and unsteady gait. The Sanofi Aventis trial was terminated due to patient’s developing this condition. 

World Health Organization (WHO) is an agency within the United Nations, composed of 194 member countries, dedicated to coordinating the world’s response to health emergencies while promoting well-being, disease prevention, and access to health care. WHO also establishes disease classification systems, including hematologic malignancies such as MPNs.