Prostate cancer is still a major challenge, due to its unacceptably high mortality and morbidity in a small proportion of patients. The development of prostate cancer is closely related to local infection and/or inflammation, which is associated with dysregulated host immunity. IL-35 and IL-37, anti-inflammatory cytokines, play an important role in the maintenance of homeostasis. Dysregulated IL-35 and 37 have been detected in many autoimmune diseases. In prostate cancer patients, local and systemic expression of IL-35 is correlated with Gleason score, differentiation, invasion, as well as prognosis. IL-37 boosts radiosensitivity in prostate cancer, inhibits proliferation and induces apoptosis of prostate cancer cells. IL-35 and IL-37 enhance macrophages to polarise towards M2 form of tumour associate macrophages in the tumour micro-environment to promote tumorigenesis. However, there is no simple answer for the particular role(s) of IL-35 and IL-37 during the development of prostate cancer, which may be related to the complex nature of host immunity, consisting of leucocytes and professional antigen presentation cells. Whilst IL-35 and IL-37 promote the development of prostate cancer, the precise underlying mechanism remains to be explored. The finding provides some insight in the potential role of precision medicine in exploring targeted therapy, with the potential to boost more specific cancer killing while reducing adverse effects.