Cytogenetic analysis is a powerful technique for bone marrow diagnosis. This is the technique that I wish to use for my leukemia research. For your information, I just went to National University Hospital of Singapore (NUH) to learn the cytogenetic analysis for bone marrow diagnosis last week week. Before I go there, I need to know a little bit about this technique first. Therefore, today we will explore about this technique.
In hematological neoplasms, the specific and non-random chromosomal abnormalies are commonly found. Those abnormalities become a main factor in pathogenesis. There are some of the hematological neoplasms are defined according to the presence of specific chromosomal abnormalities rather than referring to hematological or histological features. We can see an example where a specific subtype of AML which is M4Eo/inv(16)(p13q22) /CBFβ-MYH11 fusion AML is better defined by the presence of inversion of chromosome 16. Sometimes, the presence of certain chromosomal abnormalities also provides prognostic information too. Furthermore, cytogenetic analysis is good in distinguishing a neoplastic from a reactive process. For instance, the demonstration of clonal cytogenetic abnormality proves that idiopathic hypereosinophilic syndrome is actually eosinophilic leukemia.
Protocol of Cytogenetic Analysis
As we all know, classical cytogenetic analysis can be performed only on cell suspensions which are obtained from peripheral blood or bone marrow. For hematological neoplasms, the metaphase spreads will be examined. Those metaphase spreads must be prepared from blood or bone marrow aspirates either with direct preparations or cell culture. The cells will be arrested in metaphase stage by using colcemid. After the harvesting process and dropping process, the chromosomes will be stained by using Giemsa or quinacrine mustard. With the visualization of the chromosomes, all the individual chromosomes will be classified according to their size, position of the centromere and also the banding pattern.
There are two ways that the finding can be illustrated. The findings can either be illustrated by a karyogram, which is an ordered array of chromosomes or illustrated by karyotype.
In conclusion, the protocol of processing bone marrow specimens for cytogenetic analysis is almost similar to the conventional cytogenetic test. In my next post, we will talk about the applications of cytogenetic analysis for bone marrow diagnosis and its limitations. Stay tuned in Cytogenetics Cancer Research blog!
(Reference: Bone Marrow Pathology written by Barbara J. B., David M. C., Irvin A. L. and Bridget S. W.)