PTGS2 and gastric cancer: For gastric cancer (GC), a tumor immune microenvironment (TME) signature (7) of gastric cancer based on seven features, including CD3 invasive margin (IM), CD8 IM, CD45RO center of tumor (CT), CD66b IM, CD34, periostin, and cyclooxygenase-2, which could be important for predicting survival and selecting appropriate patients for chemotherapy.