Genetic Research Report
Regions in DNA Statistically Associated with Prostate Cancer
by William J. Catalona, M.D.
Catalona and his research collaborators have just completed a
linkage analysis of DNA obtained from blood samples collected over
ten years from brothers with prostate cancer.
linkage analysis is a statistical method to determine if two kinds
of observations or results occur together more often than one would
expect by chance alone.
example, if all brothers with prostate cancer have a certain type of
gene on chromosome 16 and brothers without prostate cancer do not
share it, then the gene probably caused the prostate cancer.
In addition to providing for the development of new blood tests to
identify individuals who are genetically predisposed to prostate
cancer, further research in this area may also provide important
insights into preventing prostate cancer and developing new and more
effective treatments for the disease.
linkage analysis for this particular research project focused on
pairs of brothers who have the same genetic markers in certain
regions more often than would be expected by chance alone.
researchers discovered five new regions statistically associated
with prostate cancer. This discovery means that some fraction
of men may carry a mutated gene that predisposes them to prostate
reports have shown that certain genes in some of these regions are
commonly not present. These "missing" genes are
called tumor suppressor genes. They normally regulate cell
are like the brakes of a car. When they are deleted, the car
runs out of control. Other genes are like the
accelerator of the car and when they are turned on too much, the car
goes out of control.
study involved 230 sets of brothers (188 pairs, 40 trios, and 2
quartets) for a total of 504 men tested. In total, the
analysis involved performing approximately 209,000 genotypes
(DNA tests for variations of genetic markers which are selected at
evenly spaced distances along the length of the human chromosomes).
researchers divided the brothers into groups according to whether or
not they had a strong family history of prostate cancer, an early or
late age onset of the disease, or had a family history of breast
subanalyses discovered seven new regions in the DNA that were
associated with family history of prostate cancer, age at diagnosis,
and regions that may cause prostate cancer in men and breast cancer
genetic connection does exist between prostate and breast cancer.
There are genes that when mutated in men cause prostate cancer and
when mutated in women cause breast cancer.
a mother can pass prostate cancer on to a son and a father can pass
breast cancer to a daughter.
studies are being directed at narrowing down these regions to clone
the specific genes involved. Then, studies will be performed
to determine how these genes function normally and how they cause
cancer when they are mutated.
doctors participating in this project include Brian Suarez at
Washington University; James Burmester, James Weber, and Karl Broman
at the Marshfield Research Foundation; and John Witte and
Robert Elston at Case Western Reserve University.