Celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor approved for adult arthritis [164], is extensively being tested in clinical trials (57 registered in ReDO_Trials_DB) due to multiple reports of its potential to enhance the chemosensitivity of cancer cells and to reduce the toxicity of marketed chemotherapeutics [165–167]. Here, PTGS2 is linked to cancer.