PTGS2 and colonic neoplasm: Quercetin also induces apoptosis in colon cancer cells through the regulation of p53, suppresses carcinogenesis in rat models of colon cancer through the inhibition of enzymes involved in inflammation (cyclooxygenases COX-1 and COX-2, as well as iNOS) [160], and when used in combinatorial approaches with doxorubicin is able to arrest the cell cycle in the G2/M phase [161].