Expression of the vascular endothelial growth factor receptors 1 and 2 in acute myeloid leukemia: incidence and
M A Kharfan-Dabaja1, S A Patel, A O Osunkoya
1Section of Hematology-Oncology and OU cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA. kharfama@moffitt.usf.edu
Abstract:
Vascular endothelial growth factor (VEGF) and its receptor tyrosine kinases, VEGFR-1 and VEGFR-2, are important therapeutic targets for various cancers including AML. Paraffin-embedded bone marrow samples (PE-BM) are, in most cases, the only tissue accessible to perform retrospective analyses of novel targets such as VEGF and/or its receptors. As a result, it limits our options to immunohistochemistry (IHS), or more expensive and less practical techniques such as enzyme-linked immunosorbent assay (ELISA) or fluorescence in situ hybridization (FISH). We analyzed the feasibility of IHS to measure VEGFR-1 and VEGFR-2 expression in 28 AML samples using monoclonal antibodies (moAbs) against Flt-1 (VEGFR-1) and KDR/Flk-1 (VEGFR-2). Medical records were reviewed for relevant clinical information. Expression of VEGFR-1 (+) and VEGFR-2 (+) were seen in 25% (7/28) and 43% (12/28) respectively. Forty-six percent (13/28) were dual-negatives for VEGFR-1 and VEGFR-2; 14% (4/28) were dual-positives for VEGFR-1 and VEGFR-2. An inferior survival was observed in patients whose myeloblasts express either VEGFR-1 (+) or VEGFR-2 (+), or both. Determination of expression of VEGF receptors (1 and 2) by IHS in PE-BM tissue is feasible. Prospective comparison of IHC to flow cytometry or other molecular techniques, and assessment of the prognostic significance of VEGF receptors in AML patients is warranted.
