The BCMA expression of a plasmacytoma sample from a patient with advanced MM (~3500 BCMA cDNA copies/105 cDNA actin copies) was dramatically higher than the BCMA expression of cDNA samples from several types of normal tissues (all < 500 BCMA cDNA copies/105 cDNA actin copies). This evidence concerns the gene TNFRSF17 and plasmacytoma.