It was accumulatedselectively in COX-2 positive tumors in mice and induced tumor growthinhibition by >50% but did not have any adverse effect on tumorsthatdid not express COX-2 enzyme.26 It shouldbe noted that podophyllotoxin itself does not inhibit COX-2, but whentethered to indomethacin, it does and accumulates in COX-2-expressingtumor cells. Here, PTGS2 is linked to neoplasm.