title: Matrix-assisted laser desorption/ionization imaging protocol for in situ characterization of tryptic peptide identity and distribution in formalin-fixed tissue.
abstract: BACKGROUND
  Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry provides the means to map the in situ distribution of tryptic peptides in formalin-fixed clinical tissue samples. The ability to analyze clinical samples is of great importance to further developments in the imaging field. However, there is a requirement in this field of research for additional methods describing the characterization of tryptic peptides by MALDI imaging.
  
  
  RESULTS
  This protocol gives highly detailed instructions, with examples, for (1) successfully performing tryptic peptide MALDI imaging on formalin-fixed cancer tissue using a MALDI-TOF/TOF MS instrument, (2) tentatively generating identifications through nLC/MS/MS, and (3) validating these identifications by in situ MS/MS of peptides of interest.
  
  
  CONCLUSIONS
  This protocol provides a detailed and straightforward description of the methods required for groups new to MALDI imaging to begin analysis of formalin-fixed clinical samples.
authors: Adelaide Proteomics Centre, School of Molecular and Biomedical Science, The University of Adelaide, Adelaide, Australia, 5005.
authors: Ove J R
authors: OJ
authors: Gustafsson
authors: James S
authors: JS
authors: Eddes
authors: Stephan
authors: S
authors: Meding
authors: Shaun R
authors: SR
authors: McColl
authors: Martin K
authors: MK
authors: Oehler
authors: Peter
authors: P
authors: Hoffmann
mesh_terms: D000595:Amino Acid Sequence; D002138:Calibration; D005557:Formaldehyde / Q000737:chemistry; D016591:Histocytological Preparation Techniques / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D057054:Molecular Imaging / Q000379:methods*; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000737:chemistry; D010446:Peptide Fragments / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry; D014357:Trypsin / Q000378:metabolism
chemical_list: D010446:Peptide Fragments; D005557:Formaldehyde; D014357:Trypsin