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Reuters Health Information
LONDON -- A consortium of international scientists said last
week they have
located the first gene for susceptibility to testicular cancer.
British researchers who led the study said the gene dubbed
TGCT1 on
chromosome X is inherited from the mother and can increase a man's risk of
testicular cancer by up to 50 times.
The finding brings scientists a step closer to finding the
gene, which could
lead to earlier detection, treatment and cure of the most common cancer
among young men.
"What we have achieved is the localisation of the first
testicular cancer
susceptibility gene. What we need to do now is actually isolate the gene
itself," Professor Mike Stratton, of the Institute of Cancer Research in
the
U.K., told a press conference this week.
The gene is one of about 300 on the long arm of chromosome
X. Stratton and
his colleagues hope to work out which one is TGCT1 within the next 2 to 5
years.
"This work will be facilitated enormously by the newly
emerging genome
sequence, the first draft of which we expect to see late this year,"
Stratton added, referring to the Human Genome Project, which will map all of
the genes in the human body.
Testicular cancer affects about one in 500 men and is most
common among men
aged 25 to 29. The disease has increased steadily since the 1930s. Cases in
Denmark, which along with Switzerland and Norway have the highest rates in
the world, have trebled.
Familial testicular cancer accounts for an estimated 20 percent
of cases, so
scientists know that other genes are also involved.
Doctors also suspect that environmental factors and exposure
to higher
levels of the female hormone oestrogen in the womb are contributing factors
to the increase in the disease.
The scientists working for the International Testicular Cancer
Linkage
Consortium located the TGCT1 gene by studying 134 families worldwide with
two or more cases of the disease. It is found in a third of families with a
history of the disorder.
The finding, which is the culmination of 10 years of research,
is published
in the journal Nature Genetics.
In addition to improving detection and treatment of testicular
cancer, which
has a 90 percent to 95 percent cure rate if found early, Stratton said the
discovery has wider implications for other cancers with higher death rates.
"Testicular cancer is unusual because of its high cure
rate. By finding out
more about the molecular biology of the underlying causes and its
pathogenesis we hope to be able to work out why it is so curable," he said.
"The implications of that may be that we can see why other cancers, which
are not so curable, are different."
Risk factors for testicular cancer include a family history
of the disease
and malformed or undescended testicles. There is also a higher incidence
among first-born sons and non-identical twins.
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