Genome testing can barely predict cancer

Muted expectations: genome analysis can barely detect the individual disease risk

03/04/2012

A few years ago, scientists exulted in using the deciphering of the genetic material to make diagnoses of diseases early before the outbreak possible. A new meta-study by US researchers now dampens too high expectations: The so-called genome test is no substitute for conventional preventive medical examinations, they report by means of a data collection. Especially cancer can not be detected in time.

The best medical strategy for cancer is the early removal of malignant tumors and a healthy lifestyle. This is the result of a US research team led by Professor Bert Vogelstein of the Johns Hopkins Kimmel Cancer Center in Baltimore, USA. Although the deciphering of the genome is an outstanding discovery, the associated expectations of discovering serious diseases early before the outbreak have not yet been fulfilled. For only a limited amount of risk can be derived from the decoded genetic material of humans for common diseases such as cancer. The researchers came to this conclusion after analyzing several thousand data from identical twins from previous studies. The researchers believe that „Genome testing can not replace common disease prevention strategies.“

Early diagnosis indispensable
Early dying from serious illnesses can only be achieved through "prospective screening, early diagnosis and prevention strategies“ be prevented. For this people have to do some things themselves, like „do not smoke“, regular sports and a healthy diet. Because not only the genome, but risk factors such as toxins, unhealthy lifestyle and environmental pollution sometimes lead to the formation of cancerous tumors. According to Vogelstein, medicine can only be remedied by the „Removal of cancer in early stages“ help to increase the survival rate of the patients. That will be the „Be key to lowering death rates from disease“, he adds.

Study evaluation of twin pairs
For the investigation, the researchers looked more closely at the data from 24 diseases. These diseases included various cancers such as lung cancer, pancreatic cancer, breast cancer as well as chronic metabolic diseases such as diabetes. In addition, diseases such as Alzheimer's, neurological disorders, autoimmune diseases or cardiovascular diseases such as heart attack of the subject data were evaluated. Although it is already possible today for about 90 percent of all people to determine a specific risk for at least one disease, but would most people despite negative results still suffer in the course of their lives at least one other disease. Thus, the positive and negative results may obscure the fact that in addition to the risk genes numerous other factors exist that favor the disease risk. Therefore, the study authors warn of a deceptive security and „misunderstood wellbeing“.

Hereditary cancers rather rare
For genetically examined, in whose family cancer is rather rare, the decoding of the genome is less interesting, Vogelstein said. Because „Hereditary cancers are rare in their occurrence“. Most cancerous tumors are caused by „Kenneth Kinzler from the Ludwig Center (Johns Hopkins) said, however, that in four of the diseases studied, more than 75 percent of likely patients could be identified, according to the National Health Organization Authors suffer such as diseases of the coronary artery in men, autoimmune thyroid diseases, diabetes type-I and Alzheimer's.

However, the importance of gene analysis should not be underestimated, Vogelstein said. The genetic tests for the personal risk profile are important for politics, science and the economy. Since deciphering, the cost of genetic testing has dropped significantly. The team led by Vogelstein, Kenneth Kinzler and Nicholas J. Roberts published their study results in the journal "Science Translational Medicine". Parts of the article also came from a Chicago conference on cancer in which Vogelstein participated and gave a lecture. (Sb)

Also read about genome analysis:
Genetics of marijuana decrypted
Center for Rare Diseases opened
Study: Gene protects against flu and other viruses
Germs prevent autoimmune diseases

Image: Sigrid Rossmann