TISSUE PRESERVATION AND FIXATION METHOD

摘要

This invention relates, e.g., to a composition that, at room temperature, when contacted with a sample comprising phosphoproteins, can fix and stabil ize cellular phosphoproteins, preserve cellular morphology, and allow the sa mple to be frozen to generate a cryostat frozen section suitable for molecul ar analysis. The composition comprises ( 1 ) a fixative that is effective to fix the phosphoproteins, and that has a sufficient water content to be solu ble for a stabilizer and/or a permeability enhancing agent); (2) a stabilize r, comprising (a) a kinase inhibitor and (b) a phosphatase inhibitor and, op tionally, (c) a protease (e.g., proteinase) inhibitor; and (3) a permeabilit y enhancing agent (e.g. PEG). Methods are described for preserving phosphopr oteins, using such a composition. Also described are endogenous surrogate ma rkers for monitoring protein degradation, including the loss of posttranslat ional modifications (such as phosphorylation), e.g. the following removal of a cell or tissue from a subject; and exogenous molecular sentinels (e.g. ph osphoproteins attached to magnetic nanoparticles) that allow one to evaluate the processing history of a cellular or tissue population sample.