PDCD1 and lip and oral cavity carcinoma: In the present study, it is investigated whether programmed cell death protein 1 (PD-1) is involved in the development of oral cancer pain.<h4>Methods</h4>RMP1-14, a specific anti-PD-1 antibody, was injected into spinal trigeminal nucleus caudalis (Sp5C) and measured pain behaviors using von Frey filaments and dolognawmeter.