SMALL-BATCH PROTEOMICS: To analyze the protein composition of neurons in the temporal cortex of the human brain, researchers shave a thin slice from a formalin-fixed, paraffin-embedded tissue sample and affix it to a slide. Then they use a red laser to carve away a section of the slice. Digestion reagents prep the neuronal material for proteomic analysis via mass spectrometry.© GEORGE RETSECK
By far the majority of human tissues available for research exist as formalin-fixed, paraffin-embedded (FFPE) specimens. Preserving tissues in this way maintains their structure and allows for thin slices to be prepared for histological analyses, among other things. It had been assumed, however, that this “ridiculously harsh” preservation technique was incompatible with protein studies, explains neuroscientist Stephen Ginsberg of New York University (NYU). “The thought was that the fixation irrevocably damaged the proteins.”
Indeed, the gold-standard tissue preparation for proteome analyses was thought to be snap-freezing, Ginsberg says. He adds that comparing frozen samples to formalin-fixed ones was like comparing “grapes to raisins.” But frozen samples are exceptionally scarce, so while it may not have been considered ideal in the past, obtaining protein data from ...
