PDCD1 and nasopharyngeal carcinoma: According to a study reported at the 2015 European Cancer Congress, upon treatment with pembrolizumab (anti-PD-1), more than a fifth of patients with previously treated metastatic NPC showed an objective measurable response, while two-thirds of the patients in the study experienced some degree of reduction in the size of the target lesion (Hamid et al., 2013).