OUTLINE: This is a dose escalating study of thiotepa. Initial cytoreduction and mobilization of peripheral blood stem cells (PBSC) are conducted with FHCRC protocol 506.3 (cyclophosphamide and paclitaxel) or 506.3 (cyclophosphamide and etoposide). PBSC from syngeneic twins are collected according to FHCRC protocol 753.0. Patients then undergo leukapheresis. Patients with remaining bulky disease (greater than 2 cm) after cytoreduction/mobilization may undergo surgical debulking. High dose chemotherapy begins 30-40 days after the last chemotherapy in the cytoreduction/mobilization regimen. Patients receive mitoxantrone IV infusion over 15 minutes on days -7 and -5. Thiotepa IV is administered on days -4 and -3. Peripheral blood stem cell (PBSC) infusion occurs on day 0. 60-90 days later, melphalan IV is administered over 60 minutes on day -3. Patients undergo PBSC infusion on day 0. Patients are entered in cohorts of 3. In the absence of dose-limiting toxicity (DLT), subsequent cohorts of 3 patients each receive escalating doses of thiotepa on the same schedule. If DLT is observed in 2 of 3 patients, then the next cohort of patients each receive treatment at the next lower dose level. Once 12 patients are treated at a particular dose level, then this dose is declared the maximum tolerated dose. After engraftment following melphalan, patients receive oral tamoxifen twice a day for up to 5 years or until relapse. Patients are followed every 3 months for the first year, every 6 months for the next 4 years, then annually.