Several mechanisms are responsible for tumor immune escape, including the failure to recognize tumor cells by the immune system due to reduced major histocompatibility complex class I (MHC-I) expression, immunosuppression caused by tumor-cell-released immunosuppressive factors such as TGF-β, interleukin (IL)-10, VEGF, and cyclooxygenase-2 (COX-2), and immunoresistance resulting from the induction of EMT/CSC [104, 106, 107]. The gene discussed is PTGS2; the disease is neoplasm.