A number of recent observations indicate that the immune system may control the growth of multiple myeloma. Dendritic cells are immune cells that are capable of generating powerful antitumor immune responses. The objective of this research is to optimize a vaccine for treating multiple myeloma that is composed of a mixture of dendritic cells and RNA extracted from myeloma cells. These studies should lead to clinical trials designed to evaluate the safety and effectiveness of this vaccine following stem cell transplantation.