Two-thirds of patients with AML have leukemic blasts containing chromosomal abnormalities. These abnormalities differ among the various subtypes, as indicated in the WHO classification on previous pages. Cytogenetic analysis helps to inform important clinical, prognostic, and treatment decisions. Also, the diagnosed patient can then be monitored for remission and relapse using chromosomal and molecular analysis.
The analysis of chromosome morphology is known as karyotyping. Karyotyping is performed by growing the patient's white blood cells in special media to induce cell division and replication. Cells are then treated to stop cell division at the metaphase replication stage. The cells are then lysed to release the chromosomes and stained to show the banding. A picture of the stained chromosomes is taken. The chromosomes are counted, sorted by chromosome number and paired, and then analyzed for structure and banding. Table 7 lists some of the stains used to visualize the chromosomes.
Table 7. Stains Used for Visualizing Chromosomes.| Stain Name | What the Stain Yields |
| Giemsa | g banding |
| Acridine Orange | r banding |
| Treated Giemsa | c banding |
| Quinacrine | r banding |
Newer methods include spectral karyotyping,, such as multiplex fluorescence in situ hybridization (M-FISH), which is particularly useful in more complex rearrangements. Various automated methods can also be used to perform the karyotypes and visualize the chromosomes.
The top image shows a normal karyotype (karyogram) of a male.
The lower right image shows a karyotype (karyogram) of a male with AML, which includes a translocation of chromosomes 6 and 9 (short arrows) and a further chromosomal change of an additional chromosome 8 (long arrow).
