Plasma and tumor tissue samples are collected periodically for correlative laboratory studies. Plasma and tumor tissue samples are analyzed by ELISA for measurement of tumorigenic and angiogenic markers, including p-ERK, VEGF, sVEGFR-2, and bFGF. Tumor tissue samples are also analyzed by IHC for p-ERK, VEGFR2, phospho-VEGFR2, PDGFR, and phospho-PDGFR.