What are your odds of getting prostate cancer?
Even if you do everything you can think of to help prevent it —
for example, if you load up on fruits and vegetables, avoid red
meat, and faithfully drink a glass of red wine several times a week
— there's one thing you can't change: Your family history.
"Having prostate cancer in the family is one of
the strongest risk factors yet identified for prostate cancer,"
says William T. Isaacs, Ph.D., the William Thomas Gerrard, Mario
Anthony Duhon and Jennifer and John Chalsty Professor of Urology.
"Although environmental factors such as diet are also important,
it's clear from multiple studies that inherited genetic factors
play a critical role in determining prostate cancer risk."
Isaacs and colleagues have been studying familial
prostate cancer for more than 14 years, and have scrutinized the
genes of more than 200 families. Their intensive genetic work has
led them to discover several genes that increase a man's risk for
prostate cancer. They've found increasing evidence that inflammation
plays an important role, and so do critical variations in the genes
involved in developing cancer. And yet, they believe, they've only
scratched the surface—that there are many more prostate cancer susceptibility
genes out there, waiting to be discovered.
The best way to identify and characterize these
new genes is to study the families who, unfortunately, have been
hardest-hit by the disease, with multiple relatives affected over
several generations. To achieve a "critical mass" of families, and
to maximize the information gathered from such families worldwide,
Isaacs and colleagues have established a collaborative research
network for scientists working in this area, called the ICPCG —
International Consortium for Prostate Cancer Genetics. Isaacs is
the ICPCG's chairman, and the principal investigator of a federally
funded grant supporting this group. Together, the consortium's 14
research teams have obtained a much larger pool of prostate cancer
families — more than 2,000 — for genetic analyses.
In one of the largest studies of its kind ever
performed, the ICPCG recently combined genetic mapping data from
more than 1,200 families with hereditary prostate cancer (with at
least three first-degree relatives affected) to pinpoint the regions
of the genome most likely to harbor prostate cancer susceptibility
genes. The scientists found that a region on chromosome 22 is most
likely the home of a gene that raises the inherited risk of prostate
cancer in general.
cancer in the
family is one of the strongest risk
factors yet identified.”
Also, in a separate study, they identified regions
on chromosomes 6, 11 and 20 as the locations of genes that make
a man more likely to develop aggressive prostate cancer. "This group
of families is particularly interesting," notes Isaacs. "Only about
10 percent of all prostate cancer families are in this category,
so their study can only be performed by large combined analyses."
Because of these studies, he adds, "we now have the critical information
necessary to identify these important prostate cancer susceptibility
genes." Isaacs and colleagues believe that finding these genes will
have a huge impact on our understanding of prostate cancer, how
best to treat it, and even how to help prevent it.