PTGS1 and cancer: In recent years, the anticancer effect of aspirin, as a repurposed drug, was intensively studied and several potential mechanisms of action were described, as follows: (i) suppression of prostaglandin E2 (PGE2) formation via COX-1 (cyclooxygenase 1) inhibition; (ii) reduction in pro-inflammatory cytokines expression via COX-2 inhibition; (iii) induction of apoptosis in cancer cells; (iv) modulation of immune response; and (v) inhibition of proto-oncogenes, etc. [16,17,18].