Inclusion Criteria:

1. Meets high risk or at potential risk for tumor lysis syndrome (TLS):

A patient is at high risk for TLS if he/she presents with:

- Hyperuricemia of malignancy (plasma uric acid > 7.5 mg/dL);

- A diagnosis of very aggressive lymphoma/leukemia based on the Revised
European-American Lymphoma (REAL) classification of lymphoma/leukemia;

- Acute myeloid leukemia (AML);

- Chronic myeloid leukemia (CML) in blast crisis; or

- High grade myelodysplastic syndrome (refractory anemia with excess blast,
chronic myelomonocytic leukemia, and refractory anemia with excess blast in
transformation) only if they have > 10% bone marrow blast involvement and are
given aggressive treatment similar to AML.

A patient is at potential risk for TLS if he/she presents with:

- A diagnosis of aggressive lymphoma/leukemia based on the REAL classification of
lymphoma/leukemia plus 1 or more of the following criteria:

- Lactate dehydrogenase (LDH) >= 2 x upper limit of normal (ULN) (IU/L)

- Stage III-IV disease

- Stage I-II disease with at least 1 lymph node/tumor > 5 cm in diameter

In addition to the above-mentioned eligibility criteria, the patients should have the
following criteria:

2. Eastern Cooperative Oncology Group (ECOG) performance status 0-3

3. Age >= 18 years

4. Life expectancy > 3 months

5. Negative pregnancy test (females of child bearing potential) and use of effective
contraceptive method (for both males and females). A pregnancy test may be performed
on serum or urine human chorionic gonadotropin (HCG).

6. Signed written informed consent