CD274 and gastric cancer: Nivolumab (Opdivo, Bristol-Myers Squibb, USA), an antibody targeting PD1 and disrupting its interaction with PD-L1 and PD-L2 and increasing T lymphocytes anti-tumoral activity has been recently approved in Japan as third-line treatment for unresectable or recurrent GC patients having already undergone 2 chemotherapeutical strategies.