MALDI-Mass Spectrometry Imaging

Biomarkers can be native to the investigated organism, or they can be external substances or derivatives (metabolites) of external substances. They can be either specific or integral and, from a chemical point of view, they can be almost any type of substance class. In the context of proteomics, biomarkers are mostly 

MALDI MS A Practical Guide to Instrumentation, Methods, and Applications, Second Edition. 

Edited by Franz Hillenkamp and Jasna Peter-Katalinic. 

One other important aspect of the definition of biomarkers is beyond the scope of the actual analytical measurement of an individual sample (from an individual patient), but rather refers to the biological variabihty and mutual interference of biomolecular effectors. Only if a certain biomolecule (or labeled compound) is found in an indicative concentration in not only one or a few patient samples but in perhaps 99% of samples in a statistically sufficient cohort, can it be denoted as a candidate for a useable biomarker. Moreover, only if this substance is found, in a statistically broad study, to be independent in either appearance or concentration of other non-disease-related effectors, can the targeted disease indeed be assumed to be indicated by the detection of this biomarker material. 

Within the context of MALDl imaging methodology, the term biomarker will be considered to have a very broad meaning. Notably, it will represent a molecular signal in a given sample that, either alone or in combination (or correlation) with a pattern of other molecular signals, can indicate a particular biochemical or biological situation, independent of any question of biomedical statistical validity and/ or reliability for an entire population of individuals. 

---

McCombie G, Staab D, Stoeckli M, et al. Spatial and spectral correlations in MALDI mass spectrometry images by clustering and multivariate analysis. Anal. Chem. 2005 77 6118-6124. 

Djidja M, Claude E, Snel M, Francese S, Scriven P, Cardan V, Clench M (2010) Novel molecular tumor classification using MALDI-mass spectrometry imaging of tissue micro-assay. Anal Bioanal Chem 397 587-601. doi 10.1007/s00216-3554-6... 

Meriaux C, Franck J, Wisztorski M, Salzet M, Fournier I (2010) Liquid ionic matrixes for MALDI mass spectrometry imaging of lipids. J Proteomics 73 1204-1218. doi 10.1016/j. jprot.2010.02.010... 

Francese S, Dani F, Traldi P, Mastrobuoni G, Pieraccini G, Moneti G (2009) MALDI mass spectrometry imaging, from its origins up to today the state of the art. Comb Chem High Throughput Screen 12 156-174... 

Agar N, Yang H, Carroll R, Lack P, Agar J (2007) Matrix solution fixation histology-compatible tissue preparation for MALDI mass spectrometry imaging. Anal Chem 79(19) 7416-7423. doi 10.1021/ac071460e... 

Zimmerman T, Rubakhin S, Sweedler J (2011) MALDI mass spectrometry imaging of neuronal cell cultures. J Am Soc Mass Spectrom 22 828-836. doi 10.1007/sl3361-011-0111-2... 

Chan, K., Lanthier, P., liu, X., Sandhu, J.K., Stanimirovic, D., and li, J. (2009) MALDI mass spectrometry imaging of gangliosides in mouse brain using ionic liquid matrix. Anal. Chim. Acta, 639, 57-61. 

Eberlin, L.S., Liu, X., Ferreira, C.R., Santagata, S., Agar, N.Y., and Cooks, R.G. 2011, Desorption electrospray ionization then MALDI mass spectrometry imaging of lipid and protein distributions in single tissue sections, Anal. Chem., 15 8366-8371. 

---