Prostate Cancer Immunotherapy: Beyond Immunity to Curability

Abstract

Metastatic prostate cancer is the second leading cause of death from cancer in the United States. It is the first prevalent cancer in which overall survival in advanced disease is modestly, but objectively, improved with outpatient delivered dendritic cell–based immunotherapy. More prostate cancer patients have enrolled through Facebook and trusted-site Internet searches in clinical trials for prostate cancer vaccine–based immunotherapy than in immunotherapy trials for lung, breast, colon, pancreas, ovarian, and bladder cancer combined in the past 7 years. Exceptional responses to anti–CTLA-4 treatment have been documented in clinics, and prostate cancer neoantigen characterization and T-cell clonotyping are in their research ascendancy. The prostate is an accessory organ; it is not required for fertility, erectile function, or urinary continence. The true evolutionary advantage of having a prostate for male mammalian physiology is a topic of speculation in seminar rooms and on bar stools, but it remains unknown. Hundreds of prostate lineage-unique proteins (PLUP) exist among the >37,000 normal human prostate lineage-unique open reading frames that can be targeted for immunologic ablation of PLUP⁺ prostate cancer cells by prostate-specific autoimmunity. This bioengineered graft-versus-prostate disease is a powerful strategy that can eliminate deaths from prostate cancer. Immunologic tolerance to prostate cancer can be overcome at every clinical stage of presentation. This Cancer Immunology at the Crossroads article aims to present advances in the past two decades of basic, translational, and clinical research in prostate cancer, including bioengineering B-cell and T-cell responses, and ongoing prostate cancer immunotherapy trials. Cancer Immunol Res; 2(11); 1034–43. ©2014 AACR.