AMP-002 and AMP-003 are designed without pegylation, yet cleavable by tumor specific enzyme Cathepsin B. This design provided impetus for a) targeting apoptogen to cancer cells using tumor specific biomarker Cathepsin B [23] sparing normal cells, b) releasing the drug near tumor sites by cleaving at valine-citrulline link, c) pegylation to make it water soluble, d) enhancing the bioavailability of AMP-001 and e) to keep it intact as a pro-drug in blood circulation for a long time to reach tumor sites. This evidence concerns the gene CTSB and cancer.