Exit of pediatric pre-B acute lymphoblastic leukaemia cells from the bone marrow to the peripheral blood is not associated with cell maturation or alterations in gene expression.
BACKGROUND
Childhood pre-B acute lymphoblastic leukemia (ALL) is a bone marrow (BM) derived disease, which often disseminates out of the BM cavity, where malignant cells to a variable degree can be found circulating in the peripheral blood (PB). Normal pre-B cells are absolutely dependent on BM stroma for survival and differentiation. It is not known whether transformed pre-B ALL cells retain any of this dependence, which possibly could impact on drug sensitivity or MRD measurements.


RESULTS
Pre-B ALL cells, highly purified by a novel method using surface expression of CD19 and immunoglobulin light chains, from BM and PB show a very high degree of similarity in gene expression patterns, with differential expression of vascular endothelial growth factor (VEGF) as a notable exception. In addition, the cell sorting procedure revealed that in 2 out of five investigated patients, a significant fraction of the malignant cells had matured beyond the pre-B cell stage.


CONCLUSIONS
The transition of ALL cells from the BM into the circulation does not demand, or result in, major changes of gene expression pattern. This might indicate an independence of BM stroma on the part of transformed pre-B cells, which contrasts with that of their normal counterparts.
Hansson
Frida
F
Department of Stem Cell Biology, Lund Center for Stem Cell Biology and Cell Therapy, Lund University, Lund, Sweden. fjmhansson@gmail.com
Toporski
Jacek
J
Månsson
Robert
R
Johansson
Bertil
B
Norén-Nyström
Ulrika
U
Jacobsen
Sten Eirik W
SE
Wiebe
Thomas
T
Larsson
Marcus
M
Sigvardsson
Mikael
M
Castor
Anders
A
D001773:Blood Cells / Q000378:metabolism*; D001854:Bone Marrow Cells / Q000378:metabolism*; D002454:Cell Differentiation; D019070:Cell Lineage; D002465:Cell Movement; D002648:Child; D015870:Gene Expression; D020869:Gene Expression Profiling; D006801:Humans; D007136:Immunoglobulins / Q000378:metabolism; D017404:In Situ Hybridization, Fluorescence; D015452:Precursor B-Cell Lymphoblastic Leukemia-Lymphoma / Q000097:blood / Q000235:genetics* / Q000276:immunology; D017154:Stromal Cells / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D007136:Immunoglobulins; D042461:Vascular Endothelial Growth Factor A