MUC1 and plasma cell myeloma: In this paper, we have shown that in vitro co-culture of PBMCs (isolated from patients with myeloma) with hybrid cell lines (generated by fusion of the APC cell line HMy2 with myeloma tumor cells) resulted in the induction and expansion of tumor antigen-specific T cells with cytotoxic and IFN-γ-releasing activity against a range of relevant TAAs expressed by myeloma cells (MUC1, hTERT, CS1, MAGE C1).