Colon Cancer Gene Traced To Possible Pilgrim Ancestor

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Main Category: Colorectal Cancer
Also Included In: Genetics
Article Date: 02 Jan 2008 - 3:00 PDT

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A married couple who migrated from England to America around 1630, at the same time as the Pilgrim Fathers, have been traced as the ancestors of hundreds of Americans who have inherited a gene that predisposes them to a type of hereditary colon cancer.

This is the finding of a study published in the journal Clinical Gastroenterology and Hepatology and carried out by researchers from the Huntsman Cancer Institute (HCI) at The University of Utah.

The researchers believe they may have found that a mutation of a gene carried by many Americans alive today and is responsible for a significant percentage of colorectal cancer cases in the US, can be traced to a common ancestor.

Research assistant professor at the University of Utah, and lead author of the study, Dr Deborah Neklason, said:

"The fact that this mutation can be traced so far back in time suggests that it could be carried by many more families in the United States than is currently known."

"In fact, this founder mutation might be related to many colon cancer cases in the United States," she added.

Neklason and colleagues studied two large families, one based in Utah and the other based in New York. The members of both families have a gene mutation that increases the risk of colorectal cancer and they have in common an ancestral couple who migrated to America from England in the 1630s.

The gene mutation causes a condition called AFAP, attenuated familial adenomatous polyposis. With preventative care and screening, the chances of developing colon cancer can be significantly reduced for individuals with this gene. Without it they have a higher than 2 in 3 chance of getting cancer by the age of 80, which compares with 1 in 24 for the general population.

Neklason explained the importance of preventative medicine in treating AFAP:

"Knowing one has the condition can be life-saving."

"Not only are affected individuals at greater risk then the general population as they grow older, but precancerous polyps are often found in mutation carriers in their late teens and colon cancer has been diagnosed in individuals in their 20s," she added.

But detection of AFAP is complicated because colon cancer generally does not appear until a person is over 50, and most sporadic, or non-hereditary, cases occur in the over 50s. Also about a third of people with AFAP have only a few polyps (the little fleshy growths that precede cancer), the same number as people without AFAP.

So knowing one's family history is important to establish AFAP as a risk factor.

"People need to talk with their family, learn their family cancer history, and share this information with their doctors," explained Neklason.

"Doctors need to be aware of AFAP, recognize people at risk, and know the screening and treatment protocols that can prevent colon cancer from developing," she said.

The Utah family investigated by Neklason and colleagues comprised 7,000 members spanning 9 generations. Their records were in the Utah Population Database (UPDB) a public research resource held at HIC. The data helped the researchers find families with a higher than usual incidence of cancer, trace particular gene mutations and analyze patterns of genetic inheritance.

0.15 per cent of all colorectal cancers reported in the state of Utah between 1966 and 1995 were traced to this one family. Based on those figures, Neklason and colleagues expected there to be eight cases of colorectal cancer among the 5,000 members of the family between 1996 and 2003.

However, previous research had already found this family had the AFAP colorectal cancer risk factor and members were given intensive education and clinical interventions which may be responsible for only one member of the family receiving a diagnosis for colorectal cancer in that period.

"Preventing seven cancers may not sound like much," said Neklason.

"But that's seven colon cancers that didn't devastate this family," she added.

On a cost level, the savings are considerable. At an estimated price tag of around 50,000 dollars to treat one case of colorectal cancer, preventing 7 cases saves 350,000 dollars. "That means a lot for any family," said Neklason.

The Pilgrim Fathers were early settlers who came to America from England and the Netherlands so they could practise their non conformist religious beliefs away from the rather stormy political environment of early 17th Century England.

They established a colony in present-day Plymouth, Massachusetts in 1620, the second successful English settlement in America, the first being in Jamestown, Virginia in 1607. Their story is a central theme in the history of the United States.

Many of the Pilgrims travelled to America on a ship called the Mayflower, and are known today as the Mayflower Pilgrims. They and their fellow travellers established a form of government based on a document called the Mayflower Compact, which is said to be the foundation of the Constitution of the United States of America.

The Mayflower Compact includes the following words:

"[we] covenant and combine ourselves together into a civil Body Politick, for our better Ordering and Preservation."

"American Founder Mutation for Attenuated Familial Adenomatous Polyposis."
Deborah W. Neklason , Jeffery Stevens , Kenneth M. Boucher , Richard A. Kerber , Nori Matsunami , Jahn Barlow , Geraldine Mineau , Mark F. Leppert , Randall W. Burt.
Clinical Gastroenterology and Hepatology 6th December 2007 (corrected proof).
DOI: 10.1016/j.cgh.2007.09.017

Click here for Abstract.

Sources: University of Utah Health Sciences press release, journal article, wikipedia, the Mayflower Society website.

Written by: Catharine Paddock
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