NEW YORK, Sep 29 (Reuters Health) -- Accumulated changes in the genetic makeup of chromosome 8 appear to parallel the progression of prostate cancer, increasing as the cancer advances, report US researchers.
The findings suggest that genetic testing may help to identify prostate cancer patients with a poor prognosis who may benefit from early, aggressive treatment.
"Prostate cancer is a leading cause of death of men in the United States, so the identification of patients whose tumor is destined to progress rapidly is a major goal of current research," according to Dr. Robert B. Jenkins and his team from the Mayo Clinic in Rochester, Minnesota. Their results are published in the September 15th issue of the Journal of the National Cancer Institute.
Using a special technique that allows cell-by-cell identification of genetic mutations, the investigators identified changes in chromosome 8 in the tumor specimens from 144 prostate cancer patients.
As the genetic makeup of chromosome 8 changed from normal to three mutations, the percentage of aggressive tumors increased from 29% to 64%, the report indicates.
One change in particular, an increase in the number of genes for a protein called c-myc, accompanied more aggressive prostate cancers, the authors report. Such patients were nearly three times as likely to have distant spread of their cancer and more than twice as likely to die from their prostate cancer.
The researchers suggest that the genetic changes in prostate cancer occur in three steps, and that progression of the cancer parallels these changes.
While the investigators believe that the c-myc gene specifically identifies patients at risk for aggressive tumors, they also report progression of prostate cancer in some patients with normal levels of the gene, suggesting that other genes may also be involved in triggering the spread of the cancer.
Nevertheless, Jenkins and colleagues suggest that the technique they used may be employed to identify patients with extra c-myc genes as those in whom prostate cancer is destined to progress at a rapid rate.
The authors conclude that these genetic changes, as they accumulate, portend a rapid progression of prostate cancer, and that patients whose cells produce excess c-myc could benefit from earlier, more aggressive anticancer therapies.