BMA Cytogenetics Analysis (CA)
1. Conventional cytogenetics analysis (CA) uses chromosome G banding.
This test is still considered the gold standard in CML monitoring by many CML doctors. CCR is
defined from the CA of 20 evaluable metaphases.
Definitions of cytogenetic responses include:
• Complete cytogenetic response or 0%Ph positive metaphase.
• Partial cytogenetic response or 1-35%Ph positive metaphases.
• Minor cytogenetic response or 36%-95%Ph positive metaphases.
• The definitions were based on the strong correlation between complete and major
cytogenetic remissions and improved long-term survival with Interferon. These prognostic
indications have been confirmed with Gleevec, showing that response and survival may be
independent of type of therapy.
Cytogenetic Analysis (CA)
• Analyze only metaphase or dividing cells.
• Require a marrow sample.
• Are time-consuming.
• CA has a wide confidence interval. Example, a patient who has 5/20 cells positive for the Ph
chromosome, the 95% confidence interval of that positivity is 9-49%.
Advantages of CA:
• It is called a routine karyotype (chromosome analysis) and the ONLY available technique to
examine ALL chromosomes. This is important because chromosomal abnormalities addition to the
Ph chromosome can occur in cells and can be a sign of accelerated phase disease. Some patients
develop chromosomal abnormalities in Ph negative cells, these are usually transient but in rare
cases can give rise to MDS or acute leukemia.
Recommendations for monitoring:
• A bone marrow aspiration with CA is recommended at diagnosis and then to confirm
complete cytogenetic response (CCR) which is when routine 20 metaphase cells show no Ph
chromosome.
• After CCR confirmation, a BMA CA test is recommended every year.