VEGF Receptors Found on CLL Cells

[Guest guest]

From ASH. Some work has gone into VEGF (a blood

vessel growth promoter) in CLL. There are several

studies which show that angiogenesis is a factor in

CLL. Yet high levels of VEGF are actually associated

with prolonged survival. Here's more on VEGF:

[4865] Receptors for Vascular Endothelial Growth

Factor (VEGF) Are Expressed on B-chronic lymphocytic

leukemia (CLL) Cells

Osnat Bairey, Yael Zimra, Esther Rabizadeh, Mati

Shaklai. Institute of Hematology and the Felsenstein

Medical Research Center, Rabin Medical Center,

Beilinson Campus, Petah Tikva, Israel

VEGF is a glycoprotein that induces the proliferation

and migration of vascular endothelial cells. Until

recently, VEGF receptors were thought to be

exclusively expressed by adult endothelial cells and

to exert their proangiogenic effect by way of

paracrine mechanisms.

Recently, however, it was shown that these receptors

are present on a subset of hematopoietic stem cells,

and on acute leukemia cells and cell lines. Since VEGF

is also produced by leukemic cells including CLL

cells, coinciding expression of VEGF receptors may

result in the generation of an autocrine loop that

supports the proliferation and survival of leukemic

cells.

We determined the percentage of cells expressing VEGF

receptors in samples from B-CLL patients. We

determined VEGF receptors expression on cells isolated

from blood from 13 CLL patients. All the samples

expressed VEGF receptors with a mean of CD19+/VEGF+

expression of 76% (range 52-92).

Thus, in CLL the leukemic cells express VEGF receptors

which may promote leukemic cell survival through an

autocrine loop.

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