F2R and cancer: In contrast to its inhibitory effects on survivin promoter activity, FL118, even at a 10 nM level, showed no inhibitory effects on luciferase activity driven by control promoters of the cyclin-dependent kinase inhibitor p21WAF1/CIP1 (p21), dihydrofolate reductase (DHFR), human thrombin receptor (HTR), or thymidine kinase (TK) genes in various cancer cell types with different p53 status (Fig. 4c–e).