No differences in PSA levels were observed between radium-223 monotherapy and the combination of abiraterone and prednisone or the combination of radium-223, abiraterone, and prednisone at the end of the study (Figure 2B), indicating that combining radium-223 with abiraterone and prednisone has no additive effect on tumor growth suppression. The gene discussed is KLK3; the disease is neoplasm.