ACUTE LYMPHOBLASTIC (LYMPHOCYTIC) LEUKEMIA (ALL)
These leukemias account for about 3 out of 4 childhood leukemias and arise in very immature forms of some white blood cells called lymphocytes.
ACUTE MYELOID LEUKEMIA (AML)
It arises from immature blood cells that normally form the myeloid white blood cells (which are not lymphocytes), red blood cells, or platelets.
AFERESIS / HEMAPHERESIS
Procedure to extract specific components of the blood. In a continuous circulation, the donor’s blood passes through a device that can separately extract platelets, red blood cells, white blood cells, plasma or stem cells and returns to the donor.
ALLOGENIC TRANSPLANTATION
Transplantation of stem cells from another person, a compatible donor. It is carried out in high-risk acute lymphoblastic leukemia, when the protocols have not given the expected results or after a relapse, and also in some cases of acute myeloid leukemia.
ANTIBODIES
These are vitally important proteins that circulate in the blood and other fluids, bringing balance to the immune system.
AUTOLOGOUS TRANSPLANTATION
Autologous transplantation of the patient’s stem cells that have been frozen before treatment; they are analyzed in the laboratory to eliminate possible cancer cells before transfusing. It is used in some cancer cases so that high-dose chemotherapy can be administered beforehand and allow rapid recovery of blood cells.
BLASTS
Immature cells found in the bone marrow that will produce white blood cells. They are not usually detected in the blood, therefore, the abnormal presence of these cells in the blood warns of a probable diagnosis of leukemia.
BONE MARROW (BM)
This is the spongy, liquid tissue found in the centre of some bones. It has a rich supply of stem cells and its main function is to produce blood cells.
BONE MARROW ASPIRACY
Procedure to remove cells from the bone marrow to examine them. The liquid sample is removed through a needle inserted into the bone, usually the iliac (hip) bone.
BONE MARROW BIOPSY
Similar procedure to bone marrow aspiration, but in this case a small piece of bone and bone marrow is removed for study.
BONE MARROW TRANSPLANTATION
Process by which all stem cells from the patient’s bone marrow are eliminated with chemotherapy and radiotherapy and healthy stem cells from another compatible person are transfused to regenerate their bone marrow.
CAR-T, Chimeric Antigen Receptor T-Cell Therapy
T cells (T lymphocytes) are removed from the child’s blood and genetically altered in the laboratory so that they have specific receptors (called chimeric antigen receptors or CAR) on their surfaces. These receptors can attack proteins on leukemia cells. The T cells are then multiplied in the laboratory and returned to the child’s blood so they can attack the leukemia cells.
CEREBROSPINAL FLUID
It surrounds the brain and spinal cord to help cushion them in case of injury and to provide nutrients.
CHEMOTHERAPY CYCLE
Chemotherapy treatment is normally administered in cycles, which refer to the time that elapses between administering one dose and the next, including the rest period between the two. The cycle duration is variable since it can last a few days or several weeks.
CHROMOSOMES
Each of the highly organized structures in which the DNA is organized. Almost all human cells contain 46 chromosomes, except sperm and egg cells. Genes, specific sequences of DNA, are the main structures that make up chromosomes. The number or shape of chromosomes may be altered in the leukemic cells.
CLINICAL TRIAL
Any experimental investigation of a substance or medicine, through its administration or application to human beings, oriented towards one of the following purposes: to establish its efficacy for a specific therapeutic, prophylactic or diagnostic indication.
COMPLETE REMISSION
It means that all evidence of the disease has disappeared.
CYTOGENETIC ANALYSIS
Samples of tissue, blood, or bone marrow are analyzed in the laboratory to identify changes in the chromosomes.
CYTOMETRY
A laboratory method of determining the number of cells, the percentage of living cells, and certain cell characteristics (such as size and shape) in a sample of blood, bone marrow, or other tissue. It also serves to identify tumor markers, such as antigens, on the cell surface.
GROWTH FACTORS
A substance produced by the body that regulates cell division and survival. Some growth factors are also made in the laboratory and used in biological therapy to help increase blood cell counts.
GVHD, GRAFT-VERSUS-HOST REACTION
The immune attack of lymphocytes in a suspension of blood or marrow cells from a donor (graft) against the tissues of the recipient (host). The immune cells most involved in this reaction are the donor’s T cells, present in the donor’s blood or marrow, the source of stem cells. The main organs damaged are the skin, the liver and the digestive tract. This reaction is rare in transplants between identical twins. The reaction may be minimal in people with a higher compatibility, or severe in people with a lower compatibility.
HEMATOLOGY
Medical specialty that deals with the study, diagnosis, treatment and prevention of diseases of the blood and the organs that participate in its production, such as the bone marrow, the spleen or the ganglia.
HEMATOPOIESIS
It is the process of formation, development and maturation of the formed elements of the blood from a common and undifferentiated cell precursor known as a pluripotent hematopoietic stem cell.
HEMATOPOIETIC STEM CELLS
These are immature cells that live in the bone marrow and develop into different blood cells (white blood cells, red blood cells and platelets) before entering the bloodstream.
HEMOGLOBIN
is a protein in red blood cells that gives them their red color and is responsible for transporting oxygen. Abnormal haemoglobin levels may be a sign of a blood disorder such as leukemia.
HLA
English acronym for human leukocyte antigens. They are the main antigens of the cells, which are recognized as foreign in the case of transplantation and condition graft rejection. Ten HLA are evaluated in the donor and in the recipient and the maximum compatibility is sought.
IMMUNE SYSTEM
The immune system protects the body from foreign invaders such as bacteria, viruses, fungi, and toxins. It is made up of different organs, cells and proteins that work together.
IMMUNOGLOBULINS
The predominant type of antibody in human blood
IMMUNOTHERAPY
Treatment to help the patient’s immune system recognize and destroy cancer cells. Various types of childhood leukemia immunotherapy are being studied, and some are already in use.
INTRATHECAL CHEMOTHERAPY
A treatment in which anticancer drugs (chemotherapy) are injected directly into the cerebrospinal fluid.
LEUKEMIA
Leukemia is a cancer of the primitive blood-producing cells, so that large numbers of abnormal blood cells are produced that infiltrate the marrow and the bloodstream. In children, it mostly presents as acute (rapidly growing) leukemia. There are different types of leukemia with different treatment options.
LEUKOCYTES or WHITE BLOOD CELLS
Blood cells that help fight infections caused by bacteria, viruses, and fungi. There are different types of white blood cells (see neutrophils and lymphocytes)
LEUKOPENIA
A decrease in the number of leukocytes (white blood cells) in the blood below standards.
LUMBAR PUNCTURE OR SPINAL PUNCTURE
It consists of inserting a needle between the bones of the spine and into the area surrounding the spinal cord, to extract cerebrospinal fluid and its subsequent analysis or to administer intrathecal chemotherapy.
LYMPH NODES
Small, bean-sized structures that contain large numbers of lymphocytes and are connected to by tiny channels called lymphatic vessels. These nodes are distributed throughout the body. In patients with lymphoma and some types of leukemia, the malignant lymphocytes grow and can enlarge the lymph nodes beyond their normal size.
LYMPHADENOPATHY
Term that indicates an increase in the size of the lymph nodes.
LYMPHOCYTES
Type of white blood cells, they can be of different types: T lymphocytes, B lymphocytes, or NK lymphocytes. The body depends on lymphocytes to recognize its own cells and reject those that do not belong to the body.
MINIMUM RESIDUAL DISEASE
(MRD) The presence of malignant hematological disease is detected by very sensitive techniques (flow cytometry, molecular studies), in patients who are in remission according to conventional morphological analysis.
MONOCLONAL ANTIBODIES
These are artificial antibodies that can be designed to attack a specific target, such as a protein on the surface of leukemia cells.
MUCOSITIS
Mucositis is an inflammation of the mucosal surface of the digestive tract, with the mouth, throat and esophagus being the most affected areas.
NEUTROPENIA
Decrease in the number of neutrophils in the blood, common in patients with leukemia or after chemotherapy.
NEUTROPHIL
It is a type of white blood cell, the most important to fight infections.
ONCOGENE
Oncogenes are responsible for transforming a normal cell into a malignant cell when they are aberrantly activated or over-activated, giving rise to an oncological process.
PANCYTOPENIA
Decrease, below normal, in the concentration of the three main types of blood cells: red blood cells, white blood cells and platelets.
PARTIAL REMISSION
This means that the disease has improved markedly by therapy, but residual evidence remains.
PATHOLOGIST
A doctor specialist in Pathology, the medical science in charge of studying and analyzing the cellular structure to try to explain the reasons for the different diseases from the morphological to the molecular point of view. To do this, a sample of a tissue or organ (biopsy, surgical specimen or cytology) is needed.
PCR, POLYMERASE CHAIN REACTION
Molecular biology technique that allows obtaining many copies of a DNA fragment starting from a minimum sample that acts as a template. This technique is part of different methodologies in the laboratory that allow, among others, to monitor measurable residual disease or detect mutations.
PETECHIAE
Small red dots appear on the skin due to a very low number of platelets, thrombocytopenia.
PLASMA
It is the liquid component of the blood without its cells (red blood cells, white blood cells and platelets)
PLASMATIC CELLS or PLASMACYTES
Cells that belong to the immune system and their role is to secrete large quantities of antibodies. They originate in the bone marrow, by differentiation of mature B lymphocytes, and subsequently travel to the spleen or lymph nodes to secrete antibodies.
PLATELETS OR THROMBOCYTES
Platelets are parts of cells that seal damaged blood vessels and help the blood clot.
PORT-A-CATH / INDIVIDUAL CATHETER
Various types of catheters are used for patients receiving intensive chemotherapy and/or nutritional supplements. An indwelling catheter is a special tube that is inserted into a large vein in the upper chest.
RBCs, RED BLOOD CELLS or ERYTHROCYTES
Blood cells responsible for the blood’s red color; their function is to transport oxygen to different parts of the body.
RELAPSE
Recurrence of the disease after being in remission.
REMISSION
The complete disappearance of a disease, usually as a result of treatment
SOMATIC MUTATION
Alteration of a gene in the cell of a specific tissue. Most cases of leukemia are caused by a somatic mutation in a primitive bone marrow (blood-forming) cell. Somatic mutations differ from germinal mutations because they are found only in that tissue: the rest of the body’s cells do not present it, so the mutations are not transmitted to offspring.
SPLEEN
An organ in the upper left part of the abdomen, just below the left side of the diaphragm. It is often affected in leukemia, especially lymphatic leukemia, non-Hodgkin’s lymphoma, and Hodgkin’s lymphoma.
THROMBOCYTOPENIA
A decrease in platelets in the blood below standards.
TRANSFUSION
It consists of the intravenously introducing blood previously donated by another person. Compatibility in blood group and Rh is required to perform a transfusion. Transfusions are frequent as support in leukemia treatments and can be:
BLOOD TRANSFUSION
It is the transfusion of all blood cells and plasma.
PLASMA TRANSFUSION
It is transfused when it is necessary to replace blood components that are not cells, such as coagulation factors.
PLATELET TRANSFUSION
Platelet concentrate that is injected in patients with low platelets (thrombopenia).
RBC TRANSFUSION
Red blood cell concentrate consists primarily of red blood cells with a small amount of fluid.
TRANSLOCATION
Displacement of a segment of a chromosome to a new place in the genome. When a translocation occurs, the genes in which the break occurs are altered.