PTEN and prostate cancer: PTEN-null prostate cancers have also been shown to present with an immunosuppressive tumor microenvironment characterized by an increased expression of IDO1 and a higher density of FoxP3+ Tregs in neoplastic glands, with distinct differences in infiltrating FoxP3+ Tregs or CD8+ T-cells at PTEN-deficient metastatic sites, such as bone, liver, and lymph nodes [81].