Jerry Radich is looking for a needle in a haystack, and he's counting on a microfluidics device to help him find it. Every year, a small fraction (about 4%) of leukemia patients develop resistance to Gleevec and related drugs. Radich and his group at the Fred Hutchinson Cancer Research Center in Seattle would like to detect resistance-causing mutations at their earliest stages, before the drugs stop working and patients stop getting better. This means detecting a singly mutated mRNA molecule against a background of 10,000 or more wild-type copies, a detection level virtually impossible using conventional methods.