Source: Wellcome Trust Sanger Institute
Date: 6 February 2009
Gene Study Finds Link to Cancer of Thyroid
By NICHOLAS WADE
Scientists have identified two genetic variations that account for 57 percent of cases of thyroid cancer, a finding that could lead to earlier detection among people at high risk for the disease.
The report, from the Icelandic company Decode Genetics, may also lead to a resurgence of interest in the quest for the genetic roots of other common maladies like heart disease and schizophrenia. Genetic variants for many such diseases have been identified, but most have turned out to account for a disappointingly small percentage of cases.
A scientific team led by Julius Gudmundsson of Decode Genetics reported Friday in the journal Nature Genetics that the two variants each lie at a site on the human genome near genes that control development of the thyroid gland. The variants are changes in a single chemical unit of the genome, which is some three billion units in length.
Compared with people who have neither variant, “the risk associated with these variants was almost sixfold, which is quite extraordinary,” said Dr. Erich M. Sturgis, a head and neck surgeon at the M. D. Anderson Cancer Center in Houston who was not connected with the research.
Dr. James A. Fagin, chief of endocrinology at the Memorial Sloan-Kettering Cancer Center in New York, said the new study was a significant advance, noting that the Decode Genetics scientists had bolstered their results by replicating the findings among Icelanders in two other populations of European descent, in Columbus, Ohio, and in Spain.
About 4 percent of people of European descent carry both variants, the scientists reported; they did not have information on other ethnic groups.
There are some 35,000 cases of thyroid cancer in the United States each year, but because of an effective treatment — removing the gland and giving patients replacement thyroid hormone — only about 1,500 people die of the disease. It would probably not be worth screening the whole population for the two new variants, at least not until the cost of genetic tests was substantially reduced.
But the test could be useful in groups at special risk, including families where one member has thyroid cancer, said Dr. Kari Stefansson, chief executive of Decode Genetics.
Dr. Fagin agreed that the ability to give such people more predictability “could be a real advantage.”
The Decode Genetics scientists found that subjects with the two variants had lower levels of thyroid-stimulating hormone in their bloodstream. That hormone, produced by the pituitary gland, directs the thyroid gland to generate its own hormones.
The thyroid-stimulating hormone also makes cells of the thyroid gland mature. Dr. Stefansson said it was conceivable that in people with the double variants the thyroid cells were not properly differentiated, and that the immature cells might be the cause of cancer. If so, supplying extra thyroid-stimulating hormone could make the cells mature and reduce the cancer risk.
Dr. Stefansson and other scientists emphasized that for now, that was just speculation.
Most genetic variants found to be associated with common diseases have turned out to account for just 1 percent or so of cases. Dr. Stefansson said the problem was that the variants had been expected to be common, and the gene chips used to analyze patients’ genomes were designed to look for common variants, not for rare ones. But it is the rare ones, he said, that now seem likely to account for most genetic disease. Evidently, natural selection winnows out disease-causing genes before they get to be common.
Dr. Stefansson said Decode Genetics had developed new and cost-effective methods to search the Icelandic population for rare variants. Those, he said, “will allow us to capture much more of the total genetic risk of common diseases.”
"'I'll make old vases for you if you want them—will make them just as I made these.' He had visions of a room full of golden brown beard. It was the most appalling thing he had ever witnessed, and there was no trickery about it. The beard had actually grown before his eyes, and it had now reached to the second button of the Clockwork man's waistcoat. And, at any moment, Mrs. Masters might return! "Worth stealing," a Society journalist lounging by remarked. "I could write a novel, only I can never think of a plot. Your old housekeeper is asleep long ago. Where do you carry your latchkey?" "Never lose your temper," he said. "It leads to apoplexy. Ah, my fine madam, you thought to pinch me, but I have pinched you instead." How does that strike you, Mr. Smith? Fancy Jerusha Abbott, (individually) ever pat me on the head, Daddy? I don't believe so-- The confusion was partly inherited from Aristotle. When discussing the psychology of that philosopher, we showed that his active Nous is no other than the idea of which we are at any moment actually conscious. Our own reason is the passive Nous, whose identity is lost in the multiplicity of objects with which it becomes identified in turn. But Aristotle was careful not to let the personality of God, or the supreme Nous, be endangered by resolving it into the totality of substantial forms which constitute Nature. God is self-conscious in the strictest sense. He thinks nothing but himself. Again, the subjective starting-point of305 Plotinus may have affected his conception of the universal Nous. A single individual may isolate himself from his fellows in so far as he is a sentient being; he cannot do so in so far as he is a rational being. His reason always addresses itself to the reason of some one else—a fact nowhere brought out so clearly as in the dialectic philosophy of Socrates and Plato. Then, when an agreement has been established, their minds, before so sharply divided, seem to be, after all, only different personifications of the same universal spirit. Hence reason, no less than its objects, comes to be conceived as both many and one. And this synthesis of contradictories meets us in modern German as well as in ancient Greek philosophy. 216 "I shall be mighty glad when we git this outfit to Chattanoogy," sighed Si. "I'm gittin' older every minute that I have 'em on my hands." "What was his name?" inquired Monty Scruggs. "Wot's worth while?" "Rose, Rose—my dear, my liddle dear—you d?an't mean——" "I'm out of practice, or I shouldn't have skinned myself like this—ah, here's Coalbran's trap. Perhaps he'll give you a lift, ma'am, into Peasmarsh." Chapter 18 "The Fair-pl?ace." "Yes," replied Black Jack, "here they are," drawing a parchment from his pocket. "This is the handwriting of a retainer called Oakley." HoME大桥未久AV手机在线观看
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