Platelet protein profiles of tumor-bearing mice correlate with tumor angiogenesis. SELDI-ToF MS expression difference maps from healthy mice (“Controls,” labeled gray), mice bearing nonangiogenic dormant tumor xenografts (“nonangiogenic,” labeled blue), and mice bearing angiogenic tumor xenografts of human liposarcoma (“angiogenic,” labeled red) are displayed in gel view. Differential expression patterns were detected for a range of peptides, and we present the most typical arrays: bFGF, PDGF, VEGF, endostatin, and albumin control. In each case, where differences in protein expressions were detected (eg, in the basic fraction [Q1 and Q2 fraction] of the platelet lysate, a difference was identified at 8200 Da), the band was further identified by purification and peptide mass fingerprinting and tandem MS (data not shown). (Abscissa) Relative MW computed from m/z value. (Ordinate) Identified peptide confirmed by immunodepletion and/or immunoprecipitation, and/or sequencing. The intensity of each of the bands correlates with relative expression level of the protein.