Postnatal diagnostic

Cytogenetic analysis of human hematopoietic cells using bone marrow aspirates is a standard practice in hematology. Cell culture improvements and processing techniques have enabled the identification of a number of recurring abnormalities in solid tumors and hematologic malignant diseases. But even more data are available for leukemias and lymphomas than for solid tumors because of the relative ease of obtaining bone marrow or peripheral blood specimens from leukemia patients.

 

The study of chromosomal abnormalities in leukemia serves two functions:

 

• The first is to assist in more accurate diagnosis, thereby providing prognostic information and allowing the more rational selection of therapy for a particular patient.
• The second is to identify the sites of consistent rearrangements, providing the precise localization required for the isolation and cloning of DNA from these regions. Using molecular techniques the function of the genes can be identified and the mechanisms whereby their altered function is involved in tumorigenesis can be determined.

 

In the past, it was assumed that cytogenetic analysis of hematologic malignant disorders was best performed directly on uncultured bone marrow samples. However, later studies indicate that analysis of cultured samples disclosed a clonal abnormality that would not have been detected if the direct method alone had been used.

Thus, for many samples, chromosomal rearrangements were often characterized only after analysis of cultured preparations.