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