GLOSSARY OF TERMS

See Monocyte


See Bone Marrow


A measurement used for some blood test results. One micro litre (μL) is an amount equal to one one-millionth of a litre, which is almost equal to a quart of blood.


See Reduced-Intensity Stem Cell Transplantation


The small amounts of cancer cells that may remain after treatment, even when blood and marrow may appear to be normal. These residual cells can only be identified by sensitive molecular techniques.


See Clonal


Antibodies made by cells belonging to a single clone. These highly specific antibodies can be produced in the laboratory. They are very important reagents for identifying and classifying disease by the immunophenotyping of cells. They also have clinical applications for targeted delivery of drugs to cancer cells and can be used to purify cells used for stem cell transplants.


Therapy using proteins made in the laboratory that either react with or attach to antigens on the cancer cells to which they are targeted. The antibodies are used therapeutically in three ways: as “naked” antibodies (monoclonal antibodies); as antibodies to which radioactive isotopes are attached (radio-immunotherapies); and as antibodies to which toxins are attached (Immunotoxins).


A type of white cell that represents about 5 to 10 per cent of the cells in normal human blood. The monocyte and the neutrophil are the two major microbe-eating and microbe-killing cells in the blood.
When monocytes leave the blood and enter the tissue, they are converted to macrophages. The macrophage is the monocyte-in-action: it can combat infection in the tissues, ingest dead cells (in this function it is called a “scavenger cell”) and assist lymphocytes in their immune functions.


A characteristic of cells that makes them resistant to the effects of several different classes of drugs. There are several forms of drug resistance.
One type of MDR involves the ability to force several drugs out of the cell. The outer wall, or membrane, of the cell contains a pump that ejects chemicals, preventing them from reaching a toxic concentration.
The resistance to drugs can be traced to the expression of genes that direct the formation of high amounts of a protein that prevents the drugs from affecting the malignant cells. If the gene or genes involved are not expressed or are weakly expressed, the cells are more sensitive to the drug’s effect. If the genes are highly expressed, the cells are less sensitive to the drug’s effect.


An alteration in a gene that results from a change to the part of the DNA that represents that gene. A “germ cell mutation” is present in the egg or the sperm and can be transmitted from parent(s) to offspring. A “somatic cell mutation” occurs in a specific tissue cell and can result in the growth of that tissue cell into a tumour. Most cancers start after a somatic mutation. In leukaemia, lymphoma or myeloma, a primitive marrow (blood-forming) or lymph node cell undergoes one or more somatic mutations, leading to the formation of a tumour. If the mutation results from a major abnormality of chromosomes, such as a translocation, it can be detected by cytogenetic examination. Sometimes the alteration in the gene is subtler and requires more sensitive tests to identify the oncogene.


See Blast Cells


A cell of the marrow that is a precursor of the mature granulocytes of the blood. Myelocytes are not present in the blood of healthy individuals.