Gene expression differences between Europeans and Africans affect response to drugs, infections

But in the process they saw several other differences. Some, including variation in the immune system's response to microbial invaders, were expected. Previous studies have found that African Americans may be more susceptible than Caucasians to infection by certain bacteria, such as Porphyromonas gingivalis that causes periodontitis.

Others were unanticipated, including significant differences in expression levels among genes involved in fundamental cellular processes such as ribosomal biogenesis, transfer RNA processing, and Notch-signaling--part of a complex system of communication that governs basic cellular activities and coordinates cell actions.

"Population differences in gene expression have only recently begun to be investigated," said Dolan, "We believe they play a significant role in susceptibility to disease and in regulating drug response. Our current research focuses on how these genetic and expression differences play a role in sensitivity to adverse effects associated with chemotherapy."

Understanding at the genetic level how individuals within and among populations vary in their response to drugs could improve treatment. The University of Chicago team worked closely with Affymetrix on new technology that enabled them to perform a very comprehensive study including evaluation of expression levels of every known gene.

The National Institutes of Health funded the study through a grant to the Pharmacogenetics of Anticancer Agents Research Group. Additional authors of the paper include Wei Zhang, Shiwei Duan, Emily O. Kistner, Wasim K. Bleibel, R. Stephanie Huang and Nancy J. Cox from the University of Chicago Medical Center and Tyson A. Clark, Tina X. Chen, Anthony C. Schweitzer and John E. Blume from Affymetrix.