Blood is collected on days 1 (prior to the first dose of dasatinib) and 15 of course 1 for measurement of VEGF pre-and post-dasatinib administration. Archived tumor tissue (tumor or core biopsy; primary or metastatic lesion) is collected for identification of the incidence of somatic mutations and polymorphisms by polymerase chain reaction and electrophoresis and for measurement of total c-src and phosphorylated src expression by immunohistochemistry.