PTGS2 and gastric cancer: This model addresses the clinical relevance of COX-2 overexpression in human gastric cancer, where COX-2 is upregulated in approximately 60%–70% of gastric carcinomas and is associated with angiogenesis, invasion, and poor prognosis (Ristimäki et al., 1997; Saukkonen et al., 2003; Wang Z. et al., 2014).