Johns Hopkins Gazette: April 3, 1995


Researchers identify genetic 
cause of cancer syndrome

     Researchers in the Medical Institutions departments of
Pathology and Oncology have identified the genetic cause of
Turcot's syndrome, a condition characterized by brain and colon
tumors. Their findings were reported in the March 30 issue of
"The New England Journal of Medicine."

     This new genetic evidence linking the two cancers may mean
that Turcot's syndrome is much more common than the medical
literature indicates, the researchers said. "These findings have
given us completely new information about the causes of brain
tumors and allow for diagnosis of the syndrome based on molecular
genetic characterization," said Stanley Hamilton, professor of
pathology and oncology who directed the study.    

     The research team studied 14 families with a history of both
colon and brain tumors who were enrolled in hereditary colon
cancer registries at Johns Hopkins and Mount Sinai Hospital in
Toronto. The investigators found mutations in two types of genes
known to cause inherited forms of colon cancer. Ten of the
families had alterations of the APC gene, a tumor suppressor gene
associated with familial adenomatous polyposis, or FAP, a disease
in which those affected get hundreds to thousands of small benign
colon and rectal tumors that eventually progress to cancer. In
two additional families, the scientists identified a mutation of
one of two mismatch repair genes, hMLH1 or hPMS2. Mismatch repair
genes act as proofreaders, looking for mistakes in the DNA
copying process and correcting them. People who inherit a
defective mismatch repair gene tend to be mutation-prone and are
at higher risk of developing cancer.

     The Johns Hopkins team collaborated with a researcher from
Hotel-Dieu de Qu´┐Żbec hospital to obtain the pathology slides
containing tissue samples from the first documented cases, which
date back to 1959. When they examined DNA from the tissue
samples, they found evidence of mutation of a mismatch repair
gene in both the brain and colon tumors.

     "Historically, Turcot's syndrome has denoted the presence of
colon polyposis and a primary tumor of the central nervous
system," Dr. Hamilton said. "This new evidence indicates that
people who inherit defective copies of either of the two types of
genes are predisposed to colon and brain cancer, and potentially
a number of other cancers as well."

     A simple blood test which could be used in high-risk
families to identify family members with the genetic alterations
is under development. Those who test positive can be followed
closely by their physicians and take advantage of available
screening tests.

Rwanda's gradual recovery 
improving public health effort 

     As the embattled tiny African nation of Rwanda slowly
re-establishes its political and military health after several
years of a brutal civil war, its best efforts may be undermined,
because of the country's ailing health care system.  

     Gil Burnham, associate professor in the School of Hygiene
and Public Health's Department of International Health, has
traveled to Rwanda several times within the past year in response
to a request for help from that country's health minister.

     "The situation was a lot better last month than it was when 
I visited in August to evaluate the public health situation," Dr. 
Burnham said. "At that time the ministry had a terrible 
staffing problem. Schools and universities lost most or all of 
their teachers. And in the area of public health, I'd say all 
persons with formal doctoral training were either killed or 
fled the country. About 80 percent of the healthcare workers 
were killed or left the country  because of the war, so there was
almost no senior staff left."

     Dr. Burnham shared his observations at a conference held
Wednesday at the School of Public Health, organized by the
student-led Health and Human Rights Group.   

     When Dr. Burnham traveled to Rwanda in August, he was struck
by the toll the war had taken on every aspect of the country,
especially its health care.

     "[The capital of] Kigali was a decimated ghost town," 
he said. "The central hospital was heavily damaged by 
bombings, looters had stripped it not only of medical 
equipment, but also its plumbing and electrical fixtures. 
Cholera and dysentery were epidemic, and death rates in 
refugee camps were unbelievable."

     During that visit, he provided the ministry with some
structure in an effort to help restore some order to the public
health system. He was unsure what he would find when he returned
seven months later to assess its progress.

     "I saw many signs of hope in February," he said. "Security
in Kigali is now pretty good, so you can actually walk around.
There's still no traffic lights, but the electricity is mostly on
and there's generally running water. And it's incredibly clean."

     Dr. Burnham is relieved to see that 85 percent of the health
centers are functioning, as are 30 of 31 district hospitals.

     "Staffing is only about half of what it was before the war,
and much of the help is being provided by workers from Uganda,
Burundi and Zaire. "But still major hospitals and teaching
institutions are functioning poorly, and there is a desperate
need for teachers and clinical specialists."

     Even though Dr. Burnham understands that his contribution to
the public health situation will not resolve all the problems, he
believes that he can provide an essential infrastructure that
will better support improvements.

     "They have no training in collecting, analyzing and using
health care information," he said. "We are teaching them basic
statistics and management skills, how to conduct manpower
planning and other health-related assessments."

     Where his efforts will lead is still unclear, Dr. Burnham 
said, but Hopkins' public health students could play a 
significant role in returning health care services to Rwanda.

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