Immunohistochemical detection of VEGF in the bone marrow of patients with chronic myeloid leukemia and correlation with the phase of disease.

We studied expression of vascular endothelial growth factor (VEGF) in paraffin-embedded bone marrow sections obtained from 15 patients with chronic myeloid leukemia (CML) in chronic phase (CP), 3 in accelerated phase (AP), 7 in myeloid blast phase (BP(M)), 6 in lymphoid blast phase (BP(L)), and in 3 normal bone marrow samples. VEGF expression was determined immunohistochemically by using an anti-VEGF antibody. In CML-CP, the distribution of VEGF showed a pattern similar to that of normal marrow. VEGF was expressed in myeloid progenitors and megakaryocytes and less abundantly in mature granulomonocytic cells, whereas erythroid cells did not stain positively for VEGF. In CML-BP(M), myeloblasts expressed substantial amounts of VEGF. By contrast, little if any VEGF was detectable in blast cells in CML-BP(L). VEGF messenger RNA (mRNA) was detected in leukemic cells in CML-BP(M) by reverse transcriptase-polymerase chain reaction, whereas blast cells in CML-BP(L) did not express substantial amounts of VEGF mRNA. Our data show that VEGF is expressed in immature myeloid cells in CML. The extent of VEGF expression depends on the phase of disease and the cell type involved in disease progression.