Our body has a few defense mechanisms against cancer cells development ie against cells growing out of control and forming tumors. One of these mechanisms works to make the cells commit suicide. This natural process is called apoptosis and it involves activation of a protein called procaspase-3. Once it is activated, the caspase-3 protein turns into an enzyme called caspase-3, which begins the cell death.

However, this mechanism doesn’t work properly in cancers and the cells are able to grow without any control. Not only are these cells resistant to the body’s mechanism but also to many chemotherapy treatments that try to mimic this natural process.

Paul Hergenrother, a chemist at the University of Illinois at Urbana-Champaign, figured out how to kick off this natural process in cancer patients. He found a synthetic molecule that directly activates procaspase-3 and should be beneficial in lung, skin, breast, kidney and colon cancers.
This molecule called molecule "procaspase activating compound number one" (PAC-1) has been distinguished among 20,000 different compounds screened.

Many cancers have increased levels of the procaspase-3 but in others, the levels are decreased depending on the cancer subtype. What scientists had to figure out was which of the cancers would be the best for the treatment with the PAC-1 molecule.
Treatment with the procaspase-3 would be more of a personalized treatment, which is much better than generalized as it would lower the number of drugs and the risks of the treatments’ side effects.