Perspectives in post-transplantation immunotherapy in breast cancer

High risk and metastatic breast cancer remain a major therapeutic challenge. Although the role of high dose chemotherapy followed by stem cell transplantation (SCT) in the overall treatment strategy is not yet well defined, it is clear that new forms of therapy such as immunotherapy will be needed to cure the majority of patients with advanced disease. We review important considerations for immunotherapy in the post-transplantation period. Experimental and clinical data suggest that immunotherapy may be most effective in a state of minimal residual disease such as that achieved following SCT. However, high dose therapy and autologous SCT result in an iatrogenic immune deficiency, which compounds the suppression of the immune system associated with tumor itself. Understanding reconstitution of a functional immune system post transplantation is critical in devising clinically effective immune interventions. A review of the clinical studies of post transplant immunotherapy for breast cancer is presented including autologous and allogeneic strategies, as well as perspectives for future development.