Inclusion Criteria:

          -  Patients must have a diagnosis of AML or acute leukemia of ambiguous lineage according
             to World Health Organization (WHO) classification with >= 5% of disease in bone marrow
             (BM)

          -  Recipients of prior allogeneic hematopoietic stem cell transplantation for AML or
             acute leukemia of ambiguous lineage are eligible if they do not have graft-versus-host
             disease (GVHD) or they have quiescent GVHD whether or not they are receiving
             immunosuppressive therapy

          -  Must have a Lansky or Karnofsky performance status of >= 50; use Karnofsky for
             patients > 16 years of age and Lansky for patients =< 16 years of age

          -  Patients must have recovered from the acute toxicity of all prior chemotherapy

          -  The following amounts of time must have elapsed prior to entry on study:

               -  2 weeks from local radiation therapy (XRT)

               -  8 weeks from prior craniospinal or if > 50% of the pelvis has been irradiated

               -  6 weeks must have elapsed if other bone marrow radiation has occurred

          -  Adequate cardiac, renal, pulmonary, and hepatic function

          -  Patient must have a life expectancy of at least 2 months

          -  Females of childbearing potential must have a negative serum pregnancy test performed
             within 7 days prior to the start of treatment

          -  Females of childbearing potential and males should agree to use adequate contraception
             (barrier method of birth control) prior to study entry and for the duration of study
             participation

        Exclusion Criteria:

          -  Recipients of prior allogeneic hematopoietic stem cell transplant (HSCT) with active
             acute or chronic GVHD

          -  Patients with history of Down's syndrome, Fanconi anemia or other known marrow failure
             condition

          -  Patients currently receiving other investigational drugs are not eligible

          -  Current concomitant chemotherapy, radiation therapy, or immunotherapy other than as
             specified in the protocol with the exception of intrathecal chemotherapy; this
             includes the tyrosine kinase inhibitor sorafenib which must not be initiated until
             patient demonstrates count recovery

          -  Patients with a systemic fungal, bacterial, viral, or other infection not controlled
             despite appropriate antibiotics or other treatment; uncontrolled systemic infections
             require infectious disease consultation for verification

          -  Patients who are platelet refractory prior to initiation of protocol therapy

          -  Pregnant or lactating patients

          -  Any significant concurrent disease, illness, or psychiatric disorder that would
             compromise patient safety or compliance, interfere with consent, study participation,
             follow up, or interpretation of study results