Sperm protein 17 is a novel cancer-testis antigen in multiple myeloma

Various studies have demonstrated the aberrant expression of normal testicu lar proteins in neoplastic cells. These proteins collectively form the new class of tumor antigens called cancer-testis (CT) antigens. Their selective normal tissue expression makes them ideal antigens for immune targeting of the malignant disease. In this study, the expression of a spermatozoa prot ein, Sp17, in multiple myeloma was investigated. It was found that Sp17 is detectable in tumor cells from 12 of 47 (26%) myeloma patients. Reverse tra nscription polymerase chain reaction (RT-PCR) and Western blot analysis det ected Sp17 transcripts and proteins, respectively. Northern blot analysis a nd RT-PCR demonstrated that Sp17 transcripts were detected only in normal t estis, supporting its tissue specificity. Since a high proportion of normal individuals develop antibodies against Sp17 following vasectomy, Sp17 is l ikely to be a highly immunogenic protein in vivo. Sp17 is therefore a novel member of the CT antigen family and should be an ideal target for immunoth erapy of multiple myeloma. (Blood, 2001;97:1508-1510) (C) 2001 by The Ameri can Society of Hematology.