Inclusion Criteria:

- Confirmed diagnosis of relapsed high-risk neuroblastoma,Ewings sarcoma, osteogenic
sarcoma, rhabdomyosarcoma, synovial sarcoma

- Patient may have gross tumor that has been treated with multi-agent chemotherapy
prior study entry, but does not need to have gross tumor prior to study entry.

- Patients must have had a diagnosis of neuroblastoma or sarcoma either by histological
verification of neuroblastoma and/or demonstration of tumor cells in the bone marrow
with increased urinary catecholamines.

- Have received standard chemotherapy and/or SCT, and are at least 6 months
post-transplant.

- Age: Patients must be 1 - < 18 years of age when registered on study.

- Organ Function Requirements: All patients must have adequate organ function defined
as:

- Hematological Function: ANC ≥ 500; Platelet count ≥ 75.

- Renal Function: Creatinine clearance or radioisotope GFR ≥ 70ml/min/1.73 m2 OR A
maximum serum creatinine (mg/dL) based on age/gender as follows: 1YO M&F = 0.6, 2-5YO
M&F = 0.8, 6-9YO M&F = 1, 10-12YO M&F = 1.2, 13-15YO M = 1.5, 13-15YO F = 1.4, 16+ M
= 1.7, 16+ F = 1.4

- Cardiac Function: Patient must have normal cardiac function documented by Ejection
fraction (> 55%) documented by echocardiogram or radionuclide MUGA evaluation OR
Fractional shortening (≥ 28%) documented by echocardiogram

- Liver Function: Total bilirubin ≤ 1.5 x normal for age, AND SGPT (ALT) and SGOT
(AST) ≤ 3 x normal for age.

- Room air pulse oximetry >94%.

- Male and female sexually active patients of reproductive age who wish to participate
must agree to use acceptable contraception.

- Lansky performance scale > 70, ECOG < 2 (Appendix I).

Exclusion Criteria:

- Patient is pregnant.

- Patients with a positive result for any of the following diagnostic tests: Hep B Ag,
Hep B Core Ab, Hep C Ab, HIV-1 Ab, HIV-2 Ab, HTLV-1 Ab, HTLV-2 Ab, RPR.

- Patient has a history of autoimmune disease, specifically inflammatory bowel disease,
systemic lupus erythematosis, or rheumatoid arthritis.

- Patient is receiving concurrent systemic steroid therapy.

- Patient has a known systemic hypersensitivity to DAC, imiquimod, or any vaccine
component.