SSX cancer testis antigens are expressed in most multiple myeloma patients: co-expression of SSX1, 2, 4, and 5 correlates with adverse prognosis and high frequencies of SSX-positive PCs.
Taylor BJ, Reiman T, Pittman JA, Keats JJ, de Bruijn DR, Mant MJ, Belch AR, Pilarski LM. J Immunother. 2005 Nov-Dec; 28(6):564-75.