PD-1/PD-L1 and immunotherapy for pancreatic cancer.

Therapy that targets programmed death 1 or programmed death 1 ligand 1 (PD-1/PD-L1), which are known as immune checkpoints, has been recently rapidly developing as oncotherapy for various carcinomas. However, this therapy has a poor effect on the treatment of pancreatic cancer with PD-1/PD-L1 blockade monotherapy. In this review, the development and limitations of anti-PD-1/PD-L1 monotherapy in pancreatic cancer are discussed. We then consider the underlying mechanism of anti-PD-1/PD-L1 monotherapy failure, combination strategies overcoming resistance to anti-PD-1/PD-L1 immunotherapy and the prospect of targeting PD-1/PD-L1 for the immunotherapy of pancreatic cancer.