Inclusion Criteria:

          -  Patients must have either (1) a diagnosis of NB as defined by international
             criteria,84 i.e., histopathology (confirmed by the MSKCC Department of Pathology) or
             BM metastases plus high urine catecholamine levels, or (2) a tumor that is
             GD2-positive.

             o A non-NB tumor is defined as GD2-positive by immunostaining with m3F8. If fresh or
             frozen tumor is not available for immunostaining, patients will be considered eligible
             if published reports show that >50% of that tumor type is GD2-positive by
             immunohistochemistry. (Note: Tissues must be fresh/frozen as fixed, paraffin-embedded
             specimens are unsuitable for anti-GD2 immunostaining). Tumors known to be GD2-
             positive by this criteria do not need immunostaining. These include: Melanoma (>50%),
             Desmoplastic small round cell tumors (70%), Osteosarcoma (88%) and Soft tissue
             sarcomas including liposarcoma, fibrosarcoma, malignant fibrous histiocytoma,
             leiomyosarcoma, and spindle cell sarcoma (93%).

          -  Patients must have either (1) refractory or relapsed high-risk NB (including
             MYCN-amplified stage 2/3/4/4S of any age and MYCN-nonamplified stage 4 in patients
             greater than 18 months of age)resistant to standard therapy*, or (2) refractory or
             relapsed GD2-positive tumor after receiving available life-prolonging therapies.

             *For NB, standard therapy generally includes 5-8 cycles of high dose induction
             chemotherapy followed by resection of gross residual tumor, with or without
             myeloablative chemotherapy with peripheral blood stem cell rescue and radiation
             therapy to the primary site. There are also salvage chemotherapy regimens for residual
             disease after standard induction therapy or for relapsed NB. Some examples of these
             chemotherapy combinations are: high-dose cyclophosphamide, topotecan and vincristine;
             high-dose cyclophosphamide, irinotecan and vincristine; irinotecan and temozolomide;
             or ifosfamide, carboplatin and etoposide.

          -  Patients must be older than 1 year of age.

          -  Prior treatment with murine 3F8 is allowed. Patients with prior m3F8, hu3F8, ch14.18
             or hu14.18 treatment must have HAHA antibody titer less than or = to 1300 Elisa
             units/ml

          -  White blood cell count ≥1000/ul

          -  Absolute neutrophil count ≥500/ul

          -  Absolute lymphocyte count ≥500/ul

          -  Platelet count ≥25,000/ul

          -  No chemotherapy or immunotherapy for a minimum of three weeks prior to study
             enrollment

          -  Women of child-bearing potential must be willing to practice an effective method of
             birth control while on treatment

          -  Signed informed consent indicating awareness of the investigational nature of this
             program.

        Exclusion Criteria:

          -  Existing major organ dysfunction > grade 2, with the exception of hearing loss and
             hematologic toxicity (defined as suppression of all subtypes of WBCs, RBCs, and
             platelets).

          -  Hematologic and primary CNS malignancies

          -  Active life-threatening infection.

          -  Pregnant women or women who are breast-feeding.

          -  Inability to comply with protocol requirements.