Tumor tissue and peripheral blood mononuclear cell (PBMC) samples are collected periodically for correlative laboratory studies. PBMCs are analyzed by western blotting for total and phospho-SRC, phospho-FAK, and other relevant biomarkers. Tumor tissue samples are analyzed by IHC for total and phospho-SRC, phospho-FAK, phospho-STAT3, phospho-KIT, and phospho-PDGFR, EPHA2, and VEGF. Tumor tissue samples are also analyzed by microarray gene expression profiling to define a potential molecular signature or gene expression pattern that may predict response to dasatinib.