In triple negative breast cancer (BT-549 and MDA-MB-231) cells, human nasopharyngeal carcinoma (NPC-TW 039 and NPC-TW 076) cells and paclitaxel-resistant A549 cells, triptolide induces S phase arrest by causing DNA strand breaks, suppressing cyclin A-CDK2 complex formation and enhancing chemosensitivity to cisplatin and paclitaxel [1006–1008]. The gene discussed is CCNA2; the disease is nasopharyngeal carcinoma.