Platelet-derived VEGF, Flt-1, angiopoietin-1 and P-selectin in breast and prostate cancer: further evidence for a role of platelets in tumour angiogenesis.
BACKGROUND
Cancer is a complex multi-factorial disorder that may commonly show abnormal angiogenesis in such patients. Recently, platelets have been postulated to have a major role in both these processes, suggesting that antiplatelet strategies may be useful in cancer treatment.


METHODS
To further investigate the role of platelets in angiogenesis, we used a novel platelet lysate assay to analyse platelet contents in breast cancer (n = 30) and prostate cancer (n = 30) patients and age- and sex-matched controls (n = 60). Markers of angiogenesis (vascular endothelial growth factor (VEGF), angiopoietin-1 and-2 (Ang-1, -2), and their respective receptors (Flt-1 and Tie-2) plus a marker of platelet activation (P-selectin (P-sel)), were all measured in platelet lysate by enzyme-linked immunsorbent assay.


RESULTS
Platelet lysate from breast cancer patients contained higher levels of VEGF (P < 0.0001). Ang-1 (P = 0.0186) and P-sel (P = 0.0002), compared to healthy controls. Platelet lysate from prostate cancer patients had elevated VEGF (P = 0.008) but not Ang-1 or P-sel. There were no significant differences between levels of Fit-1 between patients and controls, and both Ang-2 and Tie-2 were undetectable in both patient groups and control platelet lysate.


CONCLUSIONS
We have shown that our previously developed platelet lysate technique could be used to measure indices of angiogenesis, and their respective receptors, and that this assay can be applied to patients with cancer. Our study also provides further evidence that platelets may influence angiogenic abnormalities in human cancer. The platelet may be a useful target in anti-cancer strategies.
Caine
Graham J
GJ
Haemostasis, Thrombosis and Vascular Biology Unit, University Department of Medicine, City Hospital, Birmingham B18 7QH, UK.
Lip
Gregory Y
GY
Blann
Andrew D
AD
D000368:Aged; D042683:Angiopoietin-1 / Q000032:analysis; D014408:Biomarkers, Tumor / Q000032:analysis*; D001792:Blood Platelets / Q000378:metabolism* / Q000502:physiology; D001943:Breast Neoplasms / Q000098:blood supply / Q000378:metabolism* / Q000473:pathology; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay; D016326:Extracellular Matrix Proteins / Q000032:analysis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000503:physiopathology; D019007:P-Selectin / Q000032:analysis; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000469:parasitology / Q000473:pathology; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis; D040281:Vascular Endothelial Growth Factor Receptor-1
D042683:Angiopoietin-1; D014408:Biomarkers, Tumor; D016326:Extracellular Matrix Proteins; D019007:P-Selectin; D042461:Vascular Endothelial Growth Factor A; C501162:FLT1 protein, human; D040281:Vascular Endothelial Growth Factor Receptor-1