PTGS2 and lung adenocarcinoma: To determine whether COX2/PGE2 signaling also affected the clinical response of patients with lung cancer to immunotherapy, we examined the expression of a previously published COX2-associated inflammatory gene expression signature (COX-IS; ref. 31) in a cohort of patients with lung adenocarcinoma treated with anti-PDL1/PD1 for which baseline expression data were available (38).