Cells taken from prostate cancers show a nine-fold increase in expression by a gene called AMACR (x-methylacyl-CoA racemase), a team of Hopkins investigators report. "This gene appears to play an important role in breakdown of branched chain fatty acid molecules such as those found in dairy products and beef," says William B. Isaacs, Ph.D., professor of urology and oncology at the Brady Urological Institute and Kimmel Cancer Center* at Johns Hopkins, and senior author of this study.
The Hopkins scientists caution that the link, if any, between increased expression of AMACR and eating beef and dairy foods is unclear and is the focus of ongoing research. The fatty acid molecules metabolized by an enzyme made by the AMACR gene are low in chicken and most fish. Several studies have shown diets high in red meat to be associated with an increased risk of prostate cancer.
"What we've learned about AMACR could not only serve as an excellent early marker for prostate cancer but also could identify new dietary or chemical means of preventing the disease," says Angelo M. De Marzo, M.D., Ph.D., co-author of the study and assistant professor of pathology, oncology, and urology at Johns Hopkins.
In the current study, Hopkins researchers used a comprehensive "gene chip" approach to simultaneously analyze the expression of more than 6500 genes and found that the AMACR gene was overexpressed in prostate cancers. They confirmed this by examining 168 prostate cancer tumors using a tissue microarray that rapidly evaluates gene expression. Using automated computer technology, researchers displayed the tissue microarrays to speed up the identification of relationships among genes and changes in normal and cancer cells.