A higher throughput assay for quantification of melphalan-induced DNA damage in peripheral blood mononuclear cells

Inter-individual differences in DNA adduct formation and repair influence the response to melphalan treatment, however, further clinical investigation of this variability requires a logistically feasible and reproducible bioassay. Our improved fluorescence-based QPCR-block assay is robust, has good precision, and improved throughput. It also incorporates direct PCR amplification from melphalan exposed PBMC using commercially available blood tubes and extraction kits to maximise the utility of this assay for future clinical studies. Using this assay we have demonstrated reproducible inter-individual differences in melphalan-induced QPCR-block across individual PBMC donors. As proof-of-principle we assessed nine healthy donors and found a 7.8 fold range in sensitivity following exposure of PBMC ex vivo. This likely reflects differences in melphalan transport into cells as well as differences in DNA adduct repair proficiency. This improved bioassay may be useful for assessment of these processes in patients about to receive melphalan treatment.