Dr. Phillip Dennis and colleagues did exactly that: they took existing HIV protease inhibitor drugs and tested 6 of them against cancer cell lines derived from 9 different human tumor types and found that three of the drugs (ritonavir, nelfinavir and saquinavir) reduced the growth of 60 of those cell lines.
In the laboratory, nelfinavir or Viracept, a first generation speific protease inhibitor designed for HIV appeared most potent (Autophagy 4(1):107-9, 2008).
http://cancerx.wordpress.com/2011/01...o-anti-cancer/
Tumor-Cell Death, Autophagy, and Immunity
http://cancerfocus.org/forum/showthread.php?t=3651
Hybrid Mode
