CML Glossary ‘C’



CADTH = Canadian Agency for Drugs and Technology in Health.  Provides the health care divisions of Canada’s federal, provincial and territorial governments with credible, impartial and evidence based information about the effectiveness and cost effectiveness of drugs and other health technologies (


*CBC = complete blood count.


*CCR = complete cytogenetic response.


CSF = cerebrospinal fluid – a specialized bodily fluid that bathes the central nervous system.


Chemotherapy = the treatment or control of cancer using drugs which interfere with cancerous (and, unfortunately, normal) cells’ ability to grow and multiply. Most chemo drugs are targeted to a specific phase of the cell cycle, and kill only cells which are both multiplying and in that particular phase.  Tyrosine kinase inhibitors are not chemotherapy drug, rather, they are anti-leukemic drugs and work in a different way.


CHF = Congestive heart failure


Chimera = a fusion of unrelated species or types. Bcr-abl is considered a chimeric gene because it results from the abnormal fusion of the “abl” gene on chromosome #9 with the “bcr” portion of chromosome #22. Classically, a chimera is a mythical monster with a lion’s head, a goat’s body and a serpent’s tail. Bcr-abl is equally monstrous in its effects!


Chromosome = in a cell nucleus, a structure containing a molecule of DNA that transmits genetic information. Each organism of a species normally has a characteristic number of chromosomes in its somatic cells; the normal number for humans is 46. The chromosomal mutation leading to CML involves chromosomes number 9 and 22 – though if the disease is untreated, other chromosomal abnormalities accumulate as well. This process is called clonal evolution.


*Chronic myelogenous (or myeloid) leukemia (CML) = a disease involving the overproduction of certain types of white (“myeloid”) blood cells. Untreated, CML progresses through three phases – chronic, accelerated, and acute or blastic phase – each phase is shorter and harder to treat than the previous phase. Also called chronic “myeloid” or “myleocytic,” or “granulocytic” leukemia


* Chronic phase = in the context here, the earliest (and generally longest) phase of CML. It is characterized by a single abnormality of marrow stem cells, which grow too fast and don’t die soon enough. During the chronic phase, CML is relatively easy to control because it does not really behave like a cancer.


Clinical trial = Trials to evaluate the safety and effectiveness of medication (in particular) using a predetermined design or protocol.  Numerous clinical trials are necessary to obtain the right (given by a specific government agency) to market a drug.


CLL = chronic lymphocytic leukemia – not covered in this primer.


*Clonal evolution = the accumulation of DNA (chromosome) mutation which occurs in untreated CML, and which leads to progression of the disease.


Clone = a colony or group of organisms, or a colony of cells derived from a single organism or cell by asexual reproduction, having identical genetic constitution.


*CML = chronic myelogenous (or myeloid) leukemia – the subject of this Primer!


CO2 = carbon dioxide


Comparative Genomic Hybridization = a highly specialized test performed on the DNA of stem cells to see whether they have mutated over time.


Complete blood count (CBC) = a

blood test that measures the proportions and total number of white blood cells, red blood cells, and platelets. It also gives information concerning the shape, size and variation of these cells. In CML, a “white cell differential” is usually performed along with the CBC. This tells which of several kinds of white cells are present, and in what proportions.


*Complete cytogenetic response =

CCR; absence of leukemic (Ph+) cells in the bone marrow by either conventional or FISH cytogenetic testing.


*Constitutive = the property of being continuously switched on. Normal marrow stem cell growth is controlled by signals from surrounding cells, but bcr-abl, the chimeric enzyme that causes CML, is “CONSTITUTIVELY active” – that is, it keeps commanding the Ph+ cells to grow and not to die, despite negative feedback from the local environment.


*Cytogenetics. = Cyto = cell; genetics refers to looking at the cells’ chromosomes, their genetic material. Two types of cytogenetics, “conventional” and FISH, are used to diagnose and follow the course of CML. Conventional cytogenetics (so called because it’s been around a long time) is a microscopic exam of up to 25 marrow cells in a phase of cell division when their chromosomes can be clearly seen and differentiated.


*Cytogenetic response (CR) = is a response to treatment of CML that occurs in the marrow, rather than just in the blood….. There are 3 levels of cytogenetic response: 1) just plain cytogenetic response (CR); 2) Major cytogenetic response (MCR); and 3) complete cytogenetic response (CCR). A plain cytogenetic response means any Ph+ cells less than what you began with; major means 35% or less, but more than 0; and complete cytogenetic response means NO Ph+ cells as measured by either conventional or FISH cytogenetic testing (though the PCR test may still be positive).


Cytopenia = a reduction in the number of blood cells


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