Posted on 04/17/2008 9:11:10 PM PDT by blam
Inherited Cancer Mutation Is Widespread In America
ScienceDaily (Apr. 18, 2008) — A gene mutation responsible for the most common form of inherited colon cancer is older and more common than formerly believed, according to a recent study.
The findings provide a better understanding of the spread and prevalence of the American Founder Mutation, a common cause in North America of Lynch syndrome, a hereditary cancer syndrome that greatly increases a person's risk for developing cancers of the colon, uterus and ovaries.
The same investigators discovered the mutation in 2003. That research identified nine families with the mutation and concluded that a German immigrant couple brought the mutation to North America in 1727.
The latest study includes an additional 32 families and indicates that the mutation is actually about 500 years old, suggesting that it arose several generations earlier in Europeans or perhaps in Native Americans.
Of the 41 families overall, most are clustered in Kentucky, Ohio and Texas.
Scientists at the Ohio State University Comprehensive Cancer Center and Creighton University conducted the study, published recently in the journal Cancer Research.
"The increased age of the American Founder Mutation means that it is significantly more prevalent in the United States than previously thought," says principal investigator Albert de la Chapelle, a researcher with Ohio State's Human Cancer Genetics program.
"Of interest is that this mutation has not been found in Europe, which is tentative evidence, along with hints from family histories, that it may have arisen in a Native American."
The new study estimates that the mutation is present in 32,150 Americans as compared with the earlier figure of 18,981. "But these numbers are theoretical and need to be substantiated by further work," de la Chapelle notes.
"This is an important public health concern," de la Chapelle says, "because individuals with a Lynch syndrome mutation can benefit from earlier and more frequent cancer surveillance."
In addition, he says, a simple, cheap genetic test can detect the mutation.
Lynch syndrome, also known as hereditary nonpolyposis colon cancer, is responsible for about one third of hereditary colon cancers, and almost 3 percent of colon cancer generally, or about 4,500 cases annually in the United States.
The initial study of nine families showed that the American Founder Mutation results in the loss of a very specific piece of a gene called MSH2 (although many other mutations also cause Lynch syndrome).
The new study linked 27 of the 41 families into seven groups through genealogic studies.
The age of the mutation was estimated using certain markers along the DNA located at either end of the mutation. Such patterns of markers are called haplotypes.
When a new person was identified for the study, the DNA on each side of the individual's mutation was tested for the markers, producing a shared haplotype. The shorter the shared haplotype, the older the mutation. This information led to the estimated age of 500 years.
"This data pushed the original founder mutation back to around 1500, plus or minus a number of years," says coauthor Heather Hampel, a genetics counselor and researcher with Ohio State's Human Cancer Genetics Program.
"The Pilgrims began arriving in the 1600s, so the mutation could have arisen first in very early settlers from Europe, or in Native Americans."
"It's unclear whether we'll ever learn who the first person was to have this mutation," Hampel says, "but it is clear that the mutation is much older than we thought and probably more widespread. For that reason, we feel it is potentially a serious public health issue, particularly in states such as Kentucky, Ohio and Texas where it is very prevalent."
Adapted from materials provided by Ohio State University Medical Center.
Bump
I had my first colonoscopy last fall at the age of 51.
I was not looking forward to it. Actually, I was dreading it.
In retrospect, it was a piece of cake. Worthwhile for the peace of mind it gave me coming from a family with a history of colon cancer. I won't mind doing it again in four years. Well, I won't mind too much...
When it was all over the doctor gave me nice page of color prints of the inside of my colon.
My favorite photo is an anterior view of the rectal vault - inside, looking out.
I hope to use it for our 2008 Christmas card.
My wife wants a picture with all the kids. We'll talk.
I hope to use it for our 2008 Christmas card.
That could be great art.
Let’s call it a Democrat’s view of the world.
Mine wasn't so unpleasant like I expected either.
That would be quite an original card, but you’re opening a real bag of worms there! I’d be leery of receiving cards from friends in the future...Can you imagine what your friends would do to get you back for such a thing?!!
You guys probably accepted the anesthesia, I refused it and thought that it was not a fun procedure.
I had one about a month ago. The most unpleasant part was the cleansing of the colon the day before.
My family doctor said that when he had it done they gave him "happy juice."
Well, I kept waiting for the "happy juice" and it never came.
I wasn't that uncomfortable, but it wasn't the payoff I was hoping for. What with the situation and all.
Definitely.
I was to have it done a couple of years ago. I had fasted, eaten only clear liquids and at 5:00pm was about to begin the purging. I literally had the jug of laxatives to my lips when the phone rang.
"The colonoscope broke. Your procedure's cancelled," said the nurse.
I felt like the condemned man in the death chamber when the governor calls.
“I wasn’t that uncomfortable, but it wasn’t the payoff I was hoping for. What with the situation and all.”
Lol
Gin and vodka are both very fine clear liquids.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.