FL118 is a structurally camptothecin (CPT) analog and a topoisomerase I (Top1) inhibitor; however, the concentration required for FL118 to show its Top1 inhibition activity is 100- to 1000-fold higher than the concentration needed for FL118 to inhibit both survivin promoter activity and cancer cell growth [101,128,129]. This evidence concerns the gene BIRC5 and cancer.