E2F1 and cancer: In LNCaP prostate cancerous cells, TQ therapy substantially increased the level of p21Cip1 (cyclin-dependent kinase inhibitor 1), p27Kip1 (cyclin-dependent kinase inhibitor 1B), and Bax and arrested the G1 to S phase transition of cancer cell cycles, along with a dramatic reduction of androgen receptor (AR) and E2F-1-associated proteins, which are required for progression of the cancer cell cycle [58].