Peripheral Stem Cell Transplantation in Treating Patients With Breast Cancer or Hematologic Cancer

OBJECTIVES: * Determine the toxicity of ex vivo expanded megakaryocytes (EVE MK) as a supplement to peripheral blood stem cell (PBSC) transplantation in patients with breast cancer or hematologic malignancies. * Compare the effect of this treatment regimen on platelet recovery and platelet function in these patients vs historical controls. * Compare the frequency of malignant cells in the EVE MK vs the uncultured PBSC collection in these patients. * Determine the optimal time of MK harvest for the production of platelets in vivo. * Determine the required number of MKs for clinical efficacy in these patients. OUTLINE: This is a randomized study. Patients are randomized to 1 of 2 durations of CD34+ culture times (6 days vs 9 days). After an initial harvest of filgrastim (G-CSF)-mobilized autologous peripheral blood stem cells (PBSC) for transplantation, patients receive one additional dose of G-CSF and undergo one additional apheresis. The CD34+ cells are cultured in the presence of recombinant human thrombopoietin, interleukin-3, and flt3 ligand to expand megakaryocytes. Patients then undergo treatment with high-dose chemotherapy (and, in some cases, total body irradiation) followed by reinfusion of the conventional PBSC harvest and the ex vivo expanded megakaryocytes. Patients are followed until blood counts recover. PROJECTED ACCRUAL: A total of 24 patients will be accrued for this study.