TITLE:

Mass Spectrometry Imaging in the Service of Human Health

ABSTRACT:

This talk will describe recent work to use desorption electrospray ionization mass spectrometry imaging (DESI-MSI) to distinguish between cancer and benign tissue regions and to grade cancerous tumors. A thin slice of tissue is mounted on an XY translation stage and bombarded by microdroplets that can dissolve lipids and other small-molecule metabolites. The resulting splash enters a high-resolution mass spectrometer allowing us to general a chemical map with an approximate resolution of 200 microns per pixel. The interpretation of the chemical map uses primarily the lasso regression technique, which minimizes the usual sum of squared errors, with a bound on the sum of the absolute values of the coefficients. The results are compared to standard histopathologic determinations. BIOGRAPHY Richard N. Zare is the Marguerite Blake Wilbur Professor of Natural Science with an appointment in the Department of Chemistry and (by courtesy) in the Department of Physics, Stanford University. His website: http://www.stanford.edu/group/Zarelab contains more than you probably want to know about him and the current interests of his research group. He expresses his deep thanks to the researchers who have made this work possible and to the various members of the Stanford Medical School for supplying samples and to Prof. Rob Tibshirani, Department of Statistics, Stanford University, whose help has been crucial to the success of this work.