Cancer is hard to treat. How is it possible to kill all the tumor cells when they’re spread throughout the body or buried deep inside an essential organ such as the brain? One possible strategy is to target the physical aspects of cancer, such as its rapid cell division (see Physics Today, August 2007, page 19) or the hastily grown, hole-riddled vessels that supply solid tumors with blood (see the article by Jennifer Grossman and Scott McNeil, Physics Today, August 2012, page 38).
Another approach is to identify and disrupt biochemical processes that occur only in cancer cells. Researchers are on the hunt for small-molecule drugs that can bind to the proteins involved in those processes and render them nonfunctional.
The search for the most effective drugs would be aided immeasurably by three-dimensional atomic-scale structures of those proteins and drug–protein complexes. But x-ray crystallography, the standard...
