Sirolimus in Treating Young Patients With Relapsed or Refractory Acute Leukemia or Non-Hodgkin's Lymphoma

DISEASE CHARACTERISTICS: * Histologically confirmed diagnosis of 1 of the following: * Acute lymphoblastic leukemia (ALL) OR acute myeloid leukemia (AML) * At least 25% blasts in the bone marrow * Recurrent or refractory disease * Non-Hodgkin's lymphoma (NHL) * Second or greater relapse as determined by physical or radiological evidence * Disease for which there is no known curative therapy PATIENT CHARACTERISTICS: Age * 21 and under Performance status * Karnofsky 50-100% (patients over 10 years of age) * Lansky 50-100% (patients 10 years of age and under) Life expectancy * At least 4 weeks Hematopoietic * Absolute neutrophil count at least 1,000/mm\^3\* * Platelet count at least 75,000/mm\^3 (transfusion independent)\* * Hemoglobin at least 8.0 g/dL (may receive red blood cells (RBC) transfusions)\* NOTE: \*Patients with ALL, AML, and NHL with tumor metastatic to bone marrow, with granulocytopenia, anemia, and/or thrombocytopenia are eligible, but will not be evaluable for hematological toxicity Hepatic * Bilirubin no greater than 1.5 times normal * alanine aminotransferase (ALT) no greater than 5 times normal * Albumin at least 2 g/dL Renal * Creatinine based on age, as follows: * No greater than 0.8 mg/dL (5 years of age and under) * No greater than 1.0 mg/dL (6 to 10 years of age) * No greater than 1.2 mg/dL (11 to 15 years of age) * No greater than 1.5 mg/dL (over 15 years of age) OR * Creatinine clearance or radioisotope glomerular filtration rate at least 70 mL/min Cardiovascular * Shortening fraction at least 28% by echocardiogram OR * Ejection fraction at least 50% by gated radionuclide Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * Able to ingest oral medication * No known allergy to sirolimus, tacrolimus, or other mammalian target of rapamycin (mTOR) inhibitors * No uncontrolled active infection * Fungal disease must be stable for at least 2 weeks prior to study entry * Documented negative blood cultures prior to study entry for patients with bacteremia * No active graft-versus-host disease PRIOR CONCURRENT THERAPY: Biologic therapy * Recovered from prior immunotherapy * More than 1 week since prior hematopoietic growth factors except for epoetin alfa * At least 7 days since prior biologic antineoplastic agents * At least 3 months since prior bone marrow or stem cell transplantation Chemotherapy * Recovered from all prior chemotherapy * More than 2 weeks since prior myelosuppressive chemotherapy (4 weeks for nitrosoureas) * Prior hydroxyurea within the past 2 weeks is allowed provided peripheral blast count has been stable or rising for at least 3 days Endocrine therapy * Prior corticosteroids within the past 2 weeks are allowed provided peripheral blast count has been stable or rising for at least 3 days Radiotherapy * Recovered from prior radiotherapy * At least 2 weeks since prior local palliative radiotherapy * At least 4 weeks since prior craniospinal radiotherapy or radiation to the pelvis of 50% or more * At least 4 weeks since prior substantial bone marrow radiotherapy * No concurrent radiotherapy, except for emergent situations or persistent extramedullary disease with resolution of bone marrow disease Surgery * Not specified Other * No other concurrent investigational antineoplastic drugs * No concurrent administration of any of the following: * Ketoconazole * Tacrolimus * Cyclosporine * Rifampin * Diltiazem