Advances in immunotherapy of castration-resistant prostate cancer: Bisphosphonates, phosphoantigens and more

Medical progress has prolonged life expectancy in patients with castration-resistant prostate cancer; however, the lack of effective therapies has fuelled an intensive search for novel modalities, including immunotherapy. Human gamma delta T-cells can be activated by endogenous pyrophosphates (phosphoantigens), or by agents that provoke their accumulation. Among the latter, aminobisphosphonates are well-established in the clinic. In this review, the possibility that the intentional activation of gamma delta T-cells in vivo by phosphoantigens, or aminobisphosphonates and interleukin-2, may represent a promising target for the design of novel and highly innovative immunotherapy in patients with prostate cancer is discussed.