Development and evaluation of procedures and methods for Proseek Multiplex

Contemporary proximity extension assays (PEAs) are used for qualitative proteinquantifications in serological samples, with possibilities for scaling assays in multiplex. Medical research can however benefit from robust immunoassays functional for assessingprotein levels in other types of biospecimens. Formalin-fixed paraffin embedded (FFPE)tissues have long been used for morphological studies. The proteome encapsulated byextensive cross-linking from formalin fixation has however impeded the development ofproteomic analysis from the vast biorepositories FFPE-tissues constitute. In this study, Ipresent a proof of concept for assessing FFPE-samples in multiplex format through PEA.Furthermore, a homogenization and protein extraction protocol for assessing fresh-frozentissue with PEA is presented, together with a novel sample buffer for which remarkable risesin protein detection can be seen in several protein assays. Together, these findings extend theapplication area of PEA to tissues together with improved quantification characteristics