PDCD1 and neoplasm: In this regard, we have shown that small molecule inhibitors (SMIs) of GSK-3 are effective in promoting viral clearance30 and our current work31 shows that GSK-3 SMI inhibition of Pdcd1 (PD-1) transcription with a small molecule inhibitor (i.e. SB415286) is as effective as anti-PD-1 and PDL-1 blocking antibodies in the control of B16 and EL-4 tumor growth.