Although A4 showed good targeting and antitumor activity in TRAIL-sensitive breast cancer cells, we found that only ~17% of pIX was linked to TRAIL.15 To enhance AML cell targeting and killing efficacy, we used a new strategy that involved expressing sTRAIL fused to the zipper protein in E. coli, which was termed zTN. This evidence concerns the gene TNFSF10 and breast cancer.