MASSterclass™

Low abundance protein biomarker assay development and screening

There is a growing recognition of the gap that lies between biomarker discovery and the final clinical assay. Discovery platforms are designed to analyse potentially thousands of analytes in parallel in a limited but well defined set of samples. The output from a typical biomarker discovery project is a long hit-list of candidates perhaps supplemented by additional proteins from the scientific literature that require statistical validation in a larger cohort of clinical samples. This is a challenging but necessary phase to eliminate the false positives and focus future efforts on candidates that demonstrate the required clinical performance either alone or in combination. Conventional validation assays, such as ELISAs, chip and solution-based multiplexed assays and western blots, require antibodies that are often unavailable or of poor quality. The process of generating antibodies is time consuming and costly and is therefore not a practical solution for screening the hit-list of proteins derived from discovery. This has resulted in the vast majority of proteomic studies not progressing past the discovery stage unless suitable antibody reagents are readily available, which is rarely the case. Progressing candidates on the basis of availability of antibodies negates the benefit of unbiased discovery and leads to a high failure rate at the verification stage.

Coupled with MASStermind^®, our highly-sensitive proteomics biomarker discovery engine we have developed MASSterclass™, a targeted mass spectrometry based antibody-free assay platform based on MRM (multiple reaction monitoring) technology. MASSterclass™ is designed for rapidly screening of biomarker candidates in a multiplex fashion derived from discovery programs in extended sets of clinical samples to prove clinical utility and performance. The platform employs a novel pre-fractionation scheme coupled with a targeted triple quadrupole MS read-out capable of reaching limits of quantitation down to the low pg/ml level. We can rapidly develop multiplex assays to proteins arising from the discovery process or other candidates (e.g. hits from genomics or literature association) to screen relative or absolute analyte abundance in different sample sets.