The model includes androgen-dependent prostate cancer cells (N) and androgen-independent (castration-resistant) cancer cells (M), dendritic cells (D), Th1 cells (T1), CD8+ T cells (T8), T regulatory cells (Tregs, or Tr), and cytokines IL-12 (I12), IL-10 (I10) and IL-2 (I2); the model includes also checkpoints PD-1 and CTLA-4 and their ligands PD-L1 and B7, respectively, and drugs. This evidence concerns the gene CTLA4 and cancer.