MTOR inhibitors such as rapamycin were previously shown to strongly suppress proliferation of myeloma cells. Now we have shown that rapamycin can also drastically kill cultured myeloma cells when combined with a conventional drug dexamethasone for myeloma patients. We plan to figure out why it can do this and test whether it can do the same thing in a mouse model. This study will provide a basis for future clinical trials of combining these two kinds of drugs and will also result in identification of new targets for developing novel drugs.