The mechanisms by which COX2 contributes to biologic behaviour of a range of tumours are not fully understood, but suggestions include a role in angiogenesis [115], upregulation of drug efflux pumps to establish multi-drug resistance [113], and a possible influence on macrophage phenotype with more pro-tumoural M2 macrophages in the presence of high COX2 [116]. The gene discussed is PTGS2; the disease is neoplasm.