Overcoming Immune Evasion in the Prostate Tumor Microenvironment: Novel Targeted Strategies to Improve Treatment Outcomes

Despite advances in diagnostic and therapeutic technology, prostate cancer remains a leading cause of morbidity and mortality among men. While androgen deprivation therapy and next-generation androgen receptor pathway inhibitors offer durable responses, the emergence of the lethal phenotype, metastatic castration-resistant prostate cancer (mCRPC) eventually develops for most. A growing body of evidence points to the tumor microenvironment (TME) as a key driver of immune evasion and therapeutic failure. This review focuses on the current knowledge of immune suppression in the prostate TME, including cancer-associated fibroblasts, myeloid-derived suppressor cells, tumor-associated macrophages, immune checkpoint pathways, and several associated key metabolic alterations. These cellular and molecular networks contribute to therapeutic resistance and disease progression and may be used as therapeutic targets. We will also examine emerging treatment strategies aimed at reprogramming the TME, as well as combination approaches incorporating immunotherapies with other signaling inhibitors. Future success in clinical therapeutic development for mCRPC will depend on rational combinations that address both tumor-intrinsic resistance and extrinsic immune suppression, with emphasis on biomarker-driven patient and treatment selection.