Autologous Bone Marrow Transplantation - Blog Science Connections

Transient Restoration of Partial Philadelphia
Chromosome Negativity After Autografting in
Chronic Myeloid Leukemia
F. Brito-Babapulle, R. E. Marcus, F. Rassool, G Ai-Pu,
K H. Th'ng, C. Dowding, D. McCarthy, D. Catovsky,
D. A. G. Galton, and J. M. Goldman
Evidence suggests that considerable numbers of Philadelphia chromosome
(Ph 1 )-negative hematopoietic stem cells may be present, albeit in quiescent
state, in the marrow of newly diagnosed patients with chronic myeloid leukemia
(CML) (1 ). Some of these Ph 1 -negative stem cells may also be present in the
circulation. Presumably, the clonal proliferation of Ph 1 -positive cells depends on
their ability to suppress the growth of these Ph 1 -negative (putatively normal)
stem cells. Because in certain clinical circumstances a Ph 1
positive-negative
mosaicism has been recognized (2) and because in other circumstances
patients have been restored to partial or complete Ph 1
negativity by administration
of cytotoxic drugs (3,4), we thought that high-dose chemotherapy (or
chemoradiotherapy) followed by autografting with blood-derived stem cells
collected at diagnosis might give similar results.
An additional rationale for developing this protocol was that we thought the
probability of a patient entering the blastic phase of the disease might be
directly proportional to the number of leukemic stem cells in the body, a
number that might be little affected by administration of cytotoxic drugs or
189