William E. Evans, PharmD

    Demystifying the human genome

    The Memphis Business Journal most recently compared Scientific Director Bill Evans, PharmD’s work to that of an FBI profiler. His adversary, however, is far more elusive than any illicit suspect because Evans is leading a team of scientists at St. Jude Children’s Research Hospital in developing genetic profiles of leukemia. Currently, thanks to four decades of research at St. Jude, the cure rate for Acute Lymphoblastic Leukemia (ALL) is 80 percent. Evans is hoping that his findings will lead to ways of eradicating this disease in the remaining 20 percent. He says that researchers also want to know if less aggressive treatment is possible for the 80 percent that survive leukemia. In addition, revealing and better understanding the genes responsible for such things as neutralizing chemotherapy could lead to knowing how to better tailor cancer-curing drugs.

    “We look at how different types of leukemia have different expressions,” says Evans.  “We also look at what different drugs are doing -- which genes are switched on and off by which drugs.”

    Evans’ research involves developing a massive genetic profile on tissue collected over time from 500 children. This will mean examining 200,000 different spots on each person’s genome.

    “There are 20-60 genes for each drug that are expressed at different levels,” says Evans. These genes are telling us how they alter their activity in response to different drugs.

    A normal genome has 3 billion locations of which many are the same for all humans. Evans is focusing his investigation, however, on the spots in the human genome that differ from individual to individual.

    Findings from this research can help move science one step closer to mass customization in medicine for other diseases, such as high blood pressure, but Evans’ focus is on increasing the cure rate for leukemia.

    “There are plenty of other uses for this research, but what we’re fighting is leukemia and how to cure that last 20 percent,” Evans says.

    Genomic profiling is an important step in pharmacogenomics, the study of genes to determine which ones control the response to drug therapy. Evans and his team of investigators hope that the results of their work will help eliminate the guesswork in designing combination treatments by identifying the subtle differences in the human genome.

    June 2004