Scientists recognize the clear advantage of the assassin approach, of course, and have successfully engineered several targeted cancer-killing drugs over the past few decades.
The problem is, assassins ain't cheap. A single course of targeted drug therapy can cost upwards of $100,000. That's largely because the drugs take a lot of effort to create--scientists have to first grow human antibodies capable of recognizing enemy cells, and then equip those cells with a weapon by attaching them to toxic molecules. The process is, apparently, as hard and time-consuming as it sounds.
But recently, a group of scientists at University of California, San Diego engineered algae to produce a human antibody with a built-in toxic weapon--a ready-made molecular cancer assassin. The researchers produced the new therapy by embedding the genetic code of the toxin P. aeruginosa into a human antibody gene, which they then spliced into the algae's DNA.