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STUDY: Blood screening can identify genetic predisposition
JOURNAL: Johns Hopkins University
AUTHORS: Feinberg, Hengmi Cui, Marcia Cruz-Correa
ABSTRACT: A simple blood test may be able to predict who is at risk of colon cancer offering a way to avoid the embarrassing ordeal of a colonoscopy.
COMMENTARY: They found a single genetic change that was much more common in people with a family history of colon cancer and extremely common in people diagnosed with colon cancer.
Feinberg, Hengmi Cui, Marcia Cruz-Correa and others tested 172 patients at a colonoscopy clinic. They were looking for a specific genetic change called loss of imprinting.
This is not a genetic mutation, but a mistake in how the genes work. People get two copies of each gene — one from each parent — but some are imprinted so that only one copy works.
Feinberg’s lab had previously found that a gene called IGF2, which controls production of insulin-like growth factor 2, had “loss of imprinting” in some forms of cancer.
“In this case both copies are working. This is a gene for cell growth and it makes sense that getting a double dose might lead to cancer,” he said. They looked for this change both in the blood and in samples taken from the patients’ colons.
Those who had colon cancer or who had it in the past were nearly 22 times as likely to have the change, they found — and they could detect it in the blood in most cases.
Now they will have to see if other patients who had the change go on to develop cancer, Feinberg said.
And if the tests hold true in larger groups of people, it may be possible to develop a quick blood test to look for colon cancer risk.