Donor Natural Killer Cells, Cyclophosphamide, and Etoposide in Treating Children and Young Adults With Relapsed or Refractory Solid Tumors

PRIMARY OBJECTIVE: I. Determine the safety, maximum tolerated dose and/or recommended phase II dose of cord blood-derived expanded allogeneic natural killer cells (expanded allogeneic cord donor natural killer \[NK\] cells) following chemotherapy. SECONDARY OBJECTIVES: I. Determine the persistence of adoptively-transferred cord NK cells after solid tumor directed chemotherapy. II. Preliminarily define the antitumor activity to adoptively transferred NK cells following the study preparative regimen in the confines of a phase I study. III. Determine the immunophenotype and function of the infused NK cell product. IV. Preliminarily evaluate for any correlate of phenotype, killer cell immunoglobulin-like receptor (kir) haplotype, and function with overall response. OUTLINE: This is a dose escalation study of cord blood derived allogeneic NK cells. Patients receive cyclophosphamide intravenously (IV) once daily (QD) over 30 minutes and etoposide IV QD over 60 minutes on days 1-5 in the absence of unacceptable toxicity. Patients then receive cord blood derived allogeneic NK cells IV on day 8. After completion of study treatment, patients are followed up at 3-4 days, and then every week for 30 days.