High Insulin Levels Can Cause Pancreatic Cancer

Scientists at University of
British Columbia have concluded after studies in mice that high insulin levels
can lead to pancreatic cancer. The study was published in Cell Metabolism. It
is the first time a causal link has been established between high insulin
levels and pancreatic cancer.
In a study published in Cell
Metabolism, researchers lowered insulin levels in mice predisposed to
developing pancreatic cancer and found that these lower levels protected the
mice against developing the disease.
The findings hold promise for
early detection and prevention of pancreatic cancer in humans.
“Pancreatic cancer can be tricky
to detect and is too often diagnosed at a late stage, making it one of the
deadliest cancers,” said James Johnson, senior co-author of the study, a
professor and member of the Diabetes Research Group in the Life Sciences Centre
at UBC. “The five-year-survival rate is less than five per cent, and incidences
of the disease are increasing alongside obesity.”
Hyperinsulinemia, a condition in
which the body produces more insulin than it needs to control blood sugar
levels, is increasingly common, found in more than one-third of obese adults,
and can be modulated by diet and lifestyle factors. “The link between
hyperinsulinemia has actually been found across multiple cancers, including
breast cancer, but pancreatic cancer has the strongest link,” said Janel Kopp,
senior co-author and associate professor in the department of cellular and
physiological sciences. “Our experiment is the first to directly test that
hypothesis, in any cancer, in any animal model.”
For the study, lead author and
PhD student Anni Zhang crossed a strain of mice that is genetically incapable
of developing a rise in insulin with a strain of mice predisposed to developing
pancreatic cancer. These and the control mice were fed a diet for a year that
was known to increase insulin levels and promote pancreatic cancer. At the end
of the yearlong study, the mice with slightly reduced insulin levels were shown
to be protected from the start of pancreatic cancer.
“No matter whether you look at
the entire pancreas, lesions or tumours, less insulin meant reduced beginnings
of cancer in the pancreas,” Johnson said.
“We don’t see a reason why this
wouldn’t be generalizable to other cancers,” added Kopp, noting they used the
same mutation as 90 per cent of pancreatic cancers in people. “Our mouse models
are extremely relevant to people.”
In addition to examining the
relationship between insulin levels and other cancers, the scientists would
like to investigate whether decreasing excess insulin produced by the body
could positively influence later stages of pancreatic cancer. They plan to work
with colleagues at BC Cancer on human clinical trials.
The study was funded by a Cancer
Research Society grant, an Innovation Grant from the Canadian Cancer Society
Research Institute, an Ideas Grant from the Pancreas Centre BC, a Canada
Graduate Scholarship and a four-year fellowship from UBC.
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