CDK12 and neoplasm: Inactivation of CDK12 leads to focal tandem duplications that increase gene fusions or mutations, thus enhancing neoantigen production and the tumor immune response (Fig. 5).351 Two of four mCRPC patients with CDK12 mutations had obvious PSA responses after administration of a PD1 inhibitor.351 A phase 2 clinical trial to evaluate the efficacy of ipilimumab and nivolumab for CDK12-mutated mCRPC is ongoing (Table 6).