PTGS2 and cancer: Previously, we have shown that pharmacological inhibition or genetic deletion of COX2, but not COX1, suppresses DOX‐induced p53 accumulation in mouse embryonic fibroblasts (MEFs) and human cancer cell lines.18 Since p53 plays an important role in cellular senescence,34 we examined whether aspirin suppresses DOX‐induced accumulation of p53 in normal human fibroblasts.