Cohorts are dosed sequentially, and escalation may stop before the 5th cohort is dosed. Each cycle will be approximately 4 weeks in length. Following Cycle 1, patients may receive an additional 4 follow-up cycles of decitabine. Cycles 2-5 will include a 20 mg/m^2 1-hour IV infusion of decitabine on Days 1-5 for all cohorts.