Inclusion Criteria

AGE:

All patients must be less than or equal to 21 years of age.

PERFORMANCE STATUS:

Patients should have an ECOG performance status of 0, 1, or 2, and a life expectancy of at
least 8 weeks.

HISTOLOGIC DIAGNOSIS:

Patients with the following diagnosis, confirmed by appropriate histologic examination,
will be eligible for this study: neuroblastoma and Wilms' tumor.

MEASURABLE DISEASE:

Patients must have measurable disease. Patients with evaluable disease only (i.e.,
limited to positive bone scan or bone marrow) are eligible only if the bone involvement is
measurable by alternative imaging modalities (MRI, CT, or plain film).

PROGRESSIVE DISEASE:

Patients must have evidence of progressive disease following or during prior therapy.

HEMATOLOGIC FUNCTION:

Patients do not have to be evaluable for hematologic toxicity to be enrolled onto the
study. Patients without bone marrow involvement by tumor, with no history of BMT, and
with no prior cranio-spinal or pelvic radiation, will be considered evaluable for
hematologic toxicity.

Patients evaluable for hematologic toxicity must have adequate bone marrow function
(defined as peripheral absolute granulocyte count of greater than 1500/mm(3), hemoglobin
greater than 8.0 gm% and platelet count greater than 100,000/mm(3)).

HEPATIC FUNCTION:

Patients must have adequate liver function (bilirubin less than 2.0 mg%; SGPT less than 2
times normal).

RENAL FUNCTION:

Patients must have adequate renal function defined as a creatinine clearance greater than
or equal to 70 ml/min/1.732 or a serum creatinine based on age as follows:

equal to or less than 5 years old: maximum serum creatinine 0.8;

older than 5 but equal to or less than 10: 1.0;

older than 10 but equal to or less than 15: 1.2;

older than 15: 1.5.

RECOVERY FROM PRIOR THERAPY:

Patients must have recovered from the toxic effects of prior therapy, and must be off of
all chemotherapy for a minimum of two weeks prior to entry onto the protocol (a minimum of
six weeks for prior nitrosoureas).

INFORMED CONSENT:

All patients or their legal guardians must sign a document of informed consent indicating
their awareness of the investigational nature and the risks of this study.

No history of CNS malignant disease, hydro-cephalus, or pseudotumor cerebri.

No history of treatment with 13-cis retinoic acid within the prior three months.

Women of childbearing potential must not be pregnant or lactating.