But prostate cancer cells make another change.
Molecular biologist Jeffrey Milbrandt explains that "in the prostate, the tumors are androgen dependent, connected
to male sex hormones. When they metastasize, spread to other locations, they grow in an androgen-independent manner.
"We are examining the differences between the two in our genetic studies of prostate cancer."
Other scientists collaborating with Dr. Catalona are working on the same concern.
"The identification of genes involved in cancer metastasis remains a significant challenge," says Graham Casey, a
scientist in cancer biology.
"We are rigorously examining candidate genes to confirm their role in the metastatic process."
Aggressive Or Non-Aggressive
All prostate cancer is not the same.
Some forms are aggressive and life threatening whereas others are not. The problem now is that no one has a means of
identifying which is which.
"The PSA is a good screening test but it has no predictive value in this regard. The Gleason Score has some predictive
value but it's not precise enough to use in making decisions about life or death determining treatments," Gerhard explains.
One goal of prostate cancer researchers is to find associations between genetics and aggressiveness of tumor cells.
Scientists Casey and Witte are doing research in this area.
"In a recent study," Casey explains, "We determined a gene variant that seems to be associated with the development of more
aggressive forms of prostate cancer in African American men."
This finding is particularly significant as African American men are at a higher risk than other ethnic groups for developing
not only prostate cancer, but also more aggressive forms of the disease.
"The identification of such gene variants should enable us to better predict for all men an individuals risk for developing
aggressive forms of prostate cancer and should provide insights into prevention and treatment," Witte says.
Family Or Environment
Present research would indicate that nine per cent of those diagnosed with prostate cancer are genetically predisposed to the
Heredity is important for present genetic studies because it is from the familial genetic samples that potential gene regions
are identified for further study, but the nine per cent figure indicates that heredity is probably not the only significant factor
in actually causing the development of prostate cancer.
"The idea that any single gene is sufficient to cause all prostate cancer doesn't seem plausible," states Brian Suarez,
statistician for Dr. Catalona's research collaboration.
"Probably dozens of genes interact in ways we don't yet understand. In addition, the increase or decrease in risk that comes
from environment and diet, as well as genetic factors, will come into play. But we don't know about these interactions yet," he says.
Some scientists are beginning to study them.
"At the present time my applied research is primarily focused on deciphering risk factors for the initiation and progression of
prostate cancer," Ohio researcher John Witte says. "But our other work includes looking at the impact of diet - and diet gene
interactions - on the risk of prostate cancer.
"We have shown that using some types of family members such as siblings in controlled studies, we can work on detecting