Proteomic investigation of tissues of medical interest by MALDI MSI

Abstract

MALDI Mass Spectrometry Imaging (MALDI MS I) enables images of the distribution of endogenous/xenobiotic compounds to be obtained directly from intact tissue sections. The ability to localise thousand of ions in a single analysis, without using radioactive probes or antibodies, makes it a very powerful tool in biomarker discovery. Technological improvements of in situ proteomic protocols have recently enabled MALDI MS I to be used for the identification of up/down regulated species in both snap frozen and archived tissues such as formalin fixed paraffin embedded (FFPE) samples. A further improvement of these protocols, the incorporation of a surfactant in the enzymatic digestion step, is discussed for the investigation of protein distribution and expression from frozen and FFPE adenocarcinoma tissue sections