A novel multiplex assay for detection and quantitation of fatty acid synthase (FASN) in serum or plasma samples

Many cancers overexpress FASN which catalyzes the final synthetic step of de novo fatty acid synthesis pathway. FASN has been considered as a potential drug target for several decades now. Many publications provide evidence of the elevated FASN with aggressive tumors, but still, there are very few inhibitors of FASN that have successfully been utilized as therapeutics in the clinical arena. An accurate measurement of FASN in association with tumor-specific markers in solid tumors and serum may help to propel forward the therapeutic significance of FASN inhibitors. With this objective in mind, we are currently working on the development of a multiplex assay for detection and quantitation of FASN and Cripto-1 in serum samples. We have optimized a magnetic fluorescent bead based multiplex sandwich immunoassay for detection and quantitation of FASN and Cripto-1 (CR-1) in human serum and plasma samples. We selected Cripto-1 to pair with FASN because it is an EGF-like domain carrying growth factor associated with a number of different types of human carcinomas. We use two different monoclonal antibodies for FASN and one for CR-1 as capture antibodies covalently coupled to magnetic fluorescent beads and a mixture of two biotin-labeled detection antibodies in this assay. The streptavidin-phycoerythrin (SAPE) conjugate is used to report the positive capture of a target in this assay. We have also included various internal controls in this assay to monitor the assay performance and assure quality of the reagents used in each well. The dynamic range of this assay was determined to be 100pg/mL to 100 ng/mL using recombinant FASN and Cripto-1 from commercial sources. The R2 values were 0.98 and above for each of the analytes and recovery of each standard were between 90 % and 125%. We spiked recombinant FASN and Cripto-1 in normal human serum and plasma at different concentrations and spike recovery was between 70 % and 130 %. We further evaluated this assay with some commercially obtained clinical samples. This presentation includes detailed results of this study. Citation Format: Neeraja Venkateswaran, William M. Nelson. A novel multiplex assay for detection and quantitation of fatty acid synthase (FASN) in serum or plasma samples [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-248.