PTGS2 and neoplasm: Evidence indicates that the senescent cells are removed by the components of the immune system including neutrophils, macrophages, and natural killer cells.76 Given the important role of prostaglandin E2 (PGE2), a major product of COX, in tumor evasion of immune surveillance,77, 78 it is possible that aspirin may block PGE2 synthesis in the senescent cells which are known to express high levels of COX2.79 Further studies with inducible COX1 or COX2 KO mice will determine the mechanism by which aspirin suppresses DOX‐induced senescence.