A Phase I/II Study of Dasatinib and Dacarbazine

Patient will receive Dacarbazine intravenously (IV), which means it is given through a needle in a vein in the arm or through a venous port (if patient already has one). Dasatinib will be given orally starting day 2 for 17 days straight (days 2 through 19) starting the day after patient receives their first dose of Dacarbazine. The therapy will be repeated every 21 days (21 days = 1 cycle). Patient may be given other drugs before each cycle to help reduce side effects of the therapy. If patient experiences severe side effects, the amount of Dacarbazine and/or Dasatinib they receive in future cycles may be decreased. Cycle 1 day 1: * Dacarbazine Intravenous * Toxicity assessment - evaluation of any side effects that patient may be experiencing * Medical history\* * Physical examination\* - measure height, weight, blood pressure, pulse, breathing rate, temperature, assessment of patient's energy and activity level (Eastern Cooperative Group \[ECOG\] Performance Status) * Blood tests (3 tablespoons) for safety tests\*- Complete blood count with differential and platelets (CBC), Comprehensive metabolic profile (CMP), \& Magnesium test \*(certain tests may not need to be performed if they were performed during screening within 1 week; study doctor will tell patient if they need to have these tests redone) Cycle 1 day 8: * Toxicity assessment - (these will be done for the first cycle of treatment, but will be discontinued for later cycles unless deemed necessary by study doctor) * CBC - (1 tablespoon) (this will be done for the first cycle of treatment, but will be discontinued for later cycles unless deemed necessary by study doctor) * Dasatinib orally Cycle 1 day 15: * Toxicity assessment - (these will be done for the first cycle of treatment, but will be discontinued for later cycles unless deemed necessary by study doctor) * CBC - (1 tablespoon) these will be done for the first cycle of treatment, but will be discontinued for later cycles unless deemed necessary by study doctor) * Dasatinib orally * Blood sample for pharmacokinetic (PK) analysis Patient will also take Dasatinib orally as instructed days: 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 16, 17, 18, 19 each cycle. Day 1 for all cycles after the first cycle: * Dacarbazine Intravenous (IV) * Dasatinib orally * Medical history * Physical examination: measure height, weight, blood pressure, pulse, breathing rate, temperature, assessment of patient's energy and activity level (ECOG Performance Status) * Blood tests (2 tablespoon) for safety tests: CMP \& CBC * An electrocardiogram (EKG) * Computed tomography (CT) scan (done every other cycle starting with cycle 2) * Toxicity assessment If patient decides not to continue participation in this study or is taken off the study by their study doctor or the sponsor they will return to the clinic for one more visit. During this visit the following procedures will be performed: * Medical history * Perform a physical examination: measure height, weight, blood pressure, pulse, breathing rate, temperature, assessment of patient's energy and activity level (Eastern Cooperative Group \[ECOG\] Performance Status) * Blood tests (2 tablespoons) for safety tests: CBC \& CMP * Toxicity assessment Patient will need to take their assigned Dasatinib dose twice daily. It may be taken with or without food.