B15
Measurement of angiogenic biomarkers in human plasma by BD FacsArray Cytometric Bead Technology
Karen L Morris, Alasdair Greystoke, Mark P Saunders, Timothy H Ward, Gordon C Jayson
Paterson Institute for Cancer Research, Manchester, UK
Angiogenesis is critical for tumor growth and metastasis and several circulating angiogenic factors such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and Angiogenin have been found to be of prognostic significance in various cancers. These potential biomarkers of angiogenesis may be quantitatively measured using various ELISA-based technologies. Multiplexing analytes reduces sample volume and analysis time. Cytometric Bead Array (CBA) technology uses antibodies attached to beads in order to capture analytes whilst a second labeled antibody is used to enable relative quantitation. As each bead has a specific spectral identity, several analytes may be assayed simultaneously as a multiplex.
Using CBA technology, IL8, VEGF, bFGF, TNF and Angiogenin were measured in plasma from 9 normal donors, 10 non-small cell lung and 9 colorectal cancer patients. Angiogenin levels in all patients exceeded the dynamic range of the assay and therefore required significant dilution and evaluation of angiogenin in a single plex assay. The remaining analytes were multiplexed with levels ranging from 0-179pg/ml (for IL-8), 0-435pg/ml (VEGF), 0-10pg/ml (TNF) and 0-50pg/ml (bFGF). IL-8 levels were significantly higher in cancer patients compared to normal donors (mean 49.9pg/ml vs. 0.82pg/ml, p=0.007). In conclusion, angiogenic biomarkers can be measured in human plasma using CBA and this is an efficient, sensitive and cost effective method of measuring these biomarkers. However, careful consideration of which analytes are multiplexed together is paramount to the success of this technology.
