What makes a target? Our understanding of disease is a model, an imagined defect in a fanciful machine. The workings of the intact organism are understood on the basis of the tools at hand and conform to the models of other world events and inventions. In the 19th century, the microscope became a useful tool and the cell was the agent of health and disease. DNA, the agents of heredity, became the basis of the most advanced therapy in the late 20th century. DNA was the target for chemotherapy, as soon as its importance in heredity was realized .
DNA as a target has fallen out of fashion. Now, we imagine the cell as a network of messages, an internet, with signals, noise and switches. These are the modern targets: growth factor receptors (and their mutations), kinases (and their mutations); the cellular equivalents of antennae and amplifiers.
This is the model that is generating today’s medicines (often ...
