Autologous Bone Marrow Transplantation - Blog Science Connections

Aberrant Gene Expression in AML 727
C - MYC C-S l S C-ABL
N PB
AML
Figure 1. Expression of c-myc, c-sis, and c-abl in normal peripheral blood and AML.
Cytospin preparations of peripheral blood samples were fixed in 75% ethanol/20% acetic
acid before hybridization with single-standard antisense RNA probes labeled with biotin.
Hybridization was detected by fluorescein isothiocyanate linked to streptavidin and was
photographed through a fluorescence microscope.
CONCLUSIONS
In relapse or in the untreated patient, detection of leukemic cells is
relatively simple (e.g., by morphology, electron microscopy, cytochemistry,
cytogenetics, and in vitro CFC assays).
Detection of leukemic cells in remission is much more difficult. We
estimate the number of leukemic cells to be 10 8
in remission. Given this
estimate, approximately 10 6
leukemic cells are present in the marrow cell
suspension to be used for transplantation, which is 1% of the total bone
marrow pool. The frequency of the leukemic cell population, therefore, is one
leukemic cell in 20,000 cells. None of the techniques for detecting leukemic
cells in relapse is either sensitive or specific enough to trace this population in
remission. Therefore, these assays cannot be used as monitor systems of the
separation techniques used to eliminate leukemic cells from remission
marrow-cell suspensions. For these reasons we have begun to investigate the
use of molecular hybridization techniques as possible sensitive detection
methods—such as detecting aberrant proto-oncogene expression—for
identifying leukemic cells.
Recently, we and other investigators have studied oncogene expression