The purpose of this study is determine the highest dose of bortezomib, a new drug for graft-versus host disease prevention, that can be given in combination with sirolimus and Tacrolimus, without causing severe side effects. This research is being done because there is no treatment that is 100% effective in preventing graft versus host disease.

The goals of this study are to:

1. Collect peripheral blood stem cells (PBSCs) from donors for transplant.
2. Determine the largest possible dose of bortezomib that can be given to recipients with various blood cancers in a safe manner.
3. Monitor the recipient for risk of infection or side affects associated with the transplant.
4. Monitor the recipient for increased immunity following transplantation.

Inclusion Criteria:

• Undergoing myeloablative peripheral blood stem cell transplantation
• Have an HLA matched-related or matched-unrelated donor (9/10 antigen or allelic mismatch or 10/10 HLA match permitted).
• Hematological malignancy including patients with: AML, ALL, NHL, Hodgkin's Disease, CLL, CML, MDS and Multiple Myeloma
• Meeting institutional standard criteria for allogeneic PBSC transplantation

Exclusion Criteria:

• Patient has >Grade 2 peripheral neuropathy within 14 days before enrollment.
• History of autologous or allogeneic transplantation
• Evidence of HIV seropositivity
• Evidence of active infection
• Patients with cardiac dysfunction as described in the protocol
• Patients with hypersensitivity to bortezomib, boron or mannitol