This study has two phases of treatment, Phase I and Phase II. The Phase I portion of the trial will consist of a dose escalation plan with 3-6 patients being enrolled into each dose cohort. The doses of Dasatinib used in Phase I are 100 mg, 150 mg, and 200 mg. The dose that is found to be tolerated the best and also has the best treatment results will be used for Phase II. An additional 29 patients will be enrolled into Phase II.