PDCD1 and prostate adenocarcinoma: Subsequently, further studies of GAD1 in prostate cancer and paraneoplastic tissue in relation to immune checkpoint showed significant associations with CD274, CTLA4, HAVCR2, LAG3, PDCD1, TIGIT and SIGLEC15, which may lead to the speculation that they were sensitive immune checkpoints for PRAD treatment and diagnosis (Fig. 5G).