Monday, March 13, 2000
Genes linked to prostate cancer risk
NEW YORK, Mar 13 (Reuters Health) -- Certain genes appear to influence the development of prostate cancer, report US researchers. Zeroing in on these genes may lead to new tests to screen for the cancer, one of the most common cancer killers in older men.

Dr. William J. Catalona of Washington University School of Medicine in St. Louis, Missouri, together with colleagues there and elsewhere, used both genetic analysis and statistical methods to evaluate blood samples obtained from members of 230 families with at least a pair of brothers diagnosed with prostate cancer.

"Five chromosomal regions gave nominal evidence for linkage," the authors report in the March issue of the American Journal of Human Genetics.

Chromosomes are the cell structures containing DNA, the material that transmits the genetic blueprint for all living organisms. Under the microscope, most chromosomes look like uneven "X's," with long and short arms. The regions discovered by the researchers were on the long arm of chromosome 2, the short arm of chromosome 12, the long arm of chromosome 15, and regions on both the long and short arms of chromosome 16.

"The strongest signal (however) in these data is found on chromosome 16q...(in) a region suspected to contain a tumor suppressor gene," they explain.

What this means is that prostate cancer may be traceable to a gene found on the long arm of chromosome 16, which somehow fails to turn off cell division, thereby permitting the out-of-control growth which defines cancerous tumors.

In addition to chromosome 16, the authors discuss an intriguing susceptibility possibly relating to chromosome 1. They point out that the short arm of that chromosome has previously been implicated in some breast cancer tumors.

In the current study, brothers with confirmed family histories of breast cancer also displayed evidence of gene abnormality in this chromosomal area, leading Catalona and his team to suggest that "one or more tumor-suppressor genes capable of inhibiting (new tumor growth) in both breast and prostate cells may be located on the short arm of chromosome 1."

"That means that a father can pass breast cancer on to his daughter and a mother can pass prostate cancer on to her son," Catalona explained to Reuters Health.

Catalona also discussed how his team's findings may ultimately impact on both the diagnosis and treatment of prostate cancer. "When we know what the genes' normal functions are and how they cause cancer when they are mutated, it will give us critical insights into the cause of prostate cancer," he said.

As a result, new blood tests will be developed "to identify individuals who may be genetically susceptible to... prostate or breast cancer, before they develop the disease," he added.

Catalona anticipates that these tests may be able to pinpoint who is at greatest risk for more aggressive forms of the disease, versus those who will have disease with slower progression. And, perhaps most important of all, these findings "may provide the basis of future strategies for preventing prostate and/or breast cancer," the researcher said.

SOURCE: American Journal of Human Genetics 2000;66.