Genetic testing: analysis of forecasts

Completed analysis
Anton Stepnov, Sharon Bagley, "Russian Newsweek" No. 24-2010
Polina Eremenko participated in the preparation of the article

One of the articles by Harvard oncologist Stacy Gray begins with a confession. "Cancer follows my family around. He was with my grandmother and mother," the researcher writes. – I always wondered if the disease would affect me. And finally I found a way to find out – I did a genetic analysis." These lines actually have nothing to do with Gray's own memories. This is an excerpt from an advertisement for the biotech company Myriad Genetics. In 2002, residents of Denver and Atlanta could see the video. Gray quoted the clip to then lash out at the company with criticism.

Gray is haunted by the propaganda of medical genetic tests. The researcher is sure that their effectiveness still needs to be proved. This is partly recognized by the companies themselves, which, however, does not prevent them from actively offering such services to anyone. Gray published her critical article seven years ago, and since then genetic analysis has become much more popular. But they also have more opponents.

Now on Gray's side are the authors of serious studies that prove that a DNA test does not always make it possible to effectively assess a person's predisposition to various diseases. Officials also listen to their arguments. In May, the heads of three large American firms received a letter from the US Congress. A large-scale investigation of their activities was launched there. Congressmen demand to provide them with official documents, to which the companies themselves would not let anyone get close. What these firms do is called Consumer Genetics - consumer genetics. This definition was invented many years ago, but such tests have become truly consumer-friendly only recently. And as soon as everyone noticed them, problems began – hard times came for sellers of genetic services.

Invention of the YearIn 2008, Time magazine once again chose the invention of the year.

It looked very simple. The photo showed a small cardboard box with a plastic test tube inside. This is a genetic testing kit from 23andMe, one of the defendants in the recently launched investigation.

You can order a set via the Internet. All that is required of the buyer is to spit into a test tube and send a saliva sample by mail. The result of the analysis will be ready in a couple of weeks – the client will receive a list of diseases to which he is predisposed by email.

The tests are based on a large number of scientific papers linking the likelihood of the disease with the presence of unfavorable genes. At one time, one such gene pretty scared a person, thanks to which these tests became possible at all. It's about Nobel laureate James Watson. Its genome was decoded in 2007. The scientist who initiated modern DNA research has made his genes public–all but one.

Watson asked to exclude from the analysis a very small section of DNA – apoE. It determines the propensity to develop Alzheimer's disease. The symptoms of this disease are very simple: slowly and inevitably advancing dementia. Soon after the loss of reason, death occurs. The scientist did not want to know his future.

Now, for some 2,000 rubles, everyone can feel like a Nobel laureate and make their own choice. Genetic tests for predisposition to Alzheimer's disease are available to everyone.

The mountain was pushing-pushingMonica Breteler from Erasmus Rotterdam Medical Center has spent a lot of time to make such tests more accurate.

She analyzed the genomes of thousands of people with Alzheimer's disease and discovered two new genetic signs of a tendency to this disease. Biotech companies would certainly have been interested in these results, but Breteler ruined everything – she decided to test her find in action. The researcher compared her method of identifying the risk of illness with what doctors are currently using. Usually, the prognosis is based on very simple data – for example, the age and gender of the patient. In addition, doctors usually pay attention to one gene – the same apoE that scared James Watson so much.

It turned out that the new Breteler method is not able to make predictions even a little more accurate. "The results have no clinical application," she wrote dryly in her article. And in a telephone conversation, the Breteler did not pick up expressions. "In most cases, knowing your genetic status doesn't give you anything new," she told Newsweek. "In the field of such predictions, our capabilities are still at the level of the Stone Age."

She is not alone in her conclusions. In March, scientists from the American National Cancer Institute published a very similar study. They compared two methods of predicting the risk of a heart attack – the old-fashioned one (taking into account blood pressure, weight and cholesterol levels in the blood) and the genetic one. And in this case, everything turned out to be not smooth at all. DNA analysis did not allow to make the forecast more accurate.

Even former enthusiasts turn into skeptics. Among them is molecular biologist David Altshuler. At one time, he led the largest project to identify unfavorable gene variants – HapMap. And recently, in an interview with a Newsweek correspondent, the scientist admitted that he considers statements about the effectiveness of genetic tests "a big exaggeration."

However, doctors have had problems with forecasts before. "Do you know what percentage of diagnostic methods in the history of medicine have stood the test of time? – says the scientist. "Just insignificant." Steve Jones, a well-known biologist from University College London, agrees with Altshuler. "The mountain pushed and pushed and gave birth to a mouse," he said in a recent article about the practical results of the work of medical geneticists.

Not only research institutes were disappointed in genetic tests. Last year, the experts of the American Medicare health insurance program recognized the ineffectiveness of the classical DNA test analysis for the tolerability of the antithrombotic drug warfarin. According to their statistics, the patient's genetic information does not help doctors much to select a safe dosage of medication. The consequences of the examination were predictable – now Medicare does not reimburse the costs of such tests.

Analysis of forecastsThe US Congress was also interested in genetic tests.

The activities of the three largest biotech companies – 23andMe, Navigenics and Pathway Genomics – will now be investigated by a special commission. "One of the reasons for the proceedings was that genetic analyses were criticized by scientists," Congressman Bart Stupak, one of the initiators of the investigation, tells Newsweek.

Stupak has a lot of experience in such matters. He chairs a special Congressional oversight subcommittee. Now he is busy with another trial – studying the situation with the oil spill in the Gulf of Mexico, committed by the British oil company BP. The congressman and three of his colleagues signed letters that the management of biotech companies received in May. So far, officials are only asking for information. "If they refuse to cooperate, we have legal tools to get the papers," Stupak says.

There is another reason that provoked the Congress. "It all started after Pathway Genomics announced its intentions to expand the market," Esther Dyson, a member of the board of directors of 23andMe, tells Newsweek. "They planned to retail their kits in pharmacies." Dyson herself is an enthusiast for genetic research. "I don't even remember when I started this hobby," says the businesswoman. "I've always been a big fan of the idea of universal accessibility of information, including genetic information." Dyson is one of the voluntary participants of the Personal Genome project. In the near future, its genome will be decoded and will become the object of several biological studies.

Dyson only partially acknowledges the skeptics' criticism. "The testing methods themselves work fine," she says. – There are some problems with interpreting the results. But there is only one way to make forecasts more accurate – to continue collecting and processing information." It is not a fact that biotech companies will have such an opportunity. "If our examination gives an unsatisfactory result, sanctions will follow," Stupak warns. "These can be demands to make changes to products, or a complete ban on them."

Portal "Eternal youth" http://vechnayamolodost.ru09.06.2010