Matt Hancock, secretary of state for health, has been widely criticised by scientists and doctors for misconstruing the results of a genetic test that he took.
In an article in the Times with the headline 'My life may have been saved this week', Hancock described the test as 'predictive' and said that he had learned from it that he was 'in the worst 10 percent for prostate cancer', and that his risk for the condition was 'about 50 percent higher than average'. The article was adapted from a similar speech he gave at the Royal Society on 20 March.
'I would never have found this out if it hadn't been for the genomic test. Tragically, so many men don't find out they have it, until it's too late. The truth is, this test may have saved my life,' he said in his speech.
However, Hancock's reaction showed he had greatly misunderstood the information he received from the genetic test. The risk estimate he reported getting was a 15 percent a likelihood of developing prostate cancer, compared with an average population risk of 11 percent.
'For all practical purposes these are basically the same number – we wouldn't see any difference between an 11 percent risk and a 15 percent risk. 15 percent is not high risk. 50 percent would be high risk,' said Professor David Curtis, of the UCL Genetics Institute and Barts and the London School of Medicine and Dentistry.
Polygenic risk scores analyse genetic variants in a range of genes linked to susceptibility to a particular condition – for example, prostate cancer. They aim to give an overall estimate of the cumulative risks from those variants. Their results are not diagnostic and they have limited clinical use. In addition, commercially available polygenic risk score tests are largely unregulated in the UK and have widely varying levels of accuracy, Professor Curtis added.
Professor Anneke Lucassen, professor of clinical genetics, University of Southampton and chair of the British Society for Genetic Medicine, said: 'I think it is unfortunate that [Hancock's] polygenic risk score has been portrayed as a strongly predictive genetic test. The claim that his life has been saved by this test is somewhat over egging the pudding.'
Hancock said that as a result of his test, he was seeking medical advice to discuss what he understood to be an elevated risk of prostate cancer.
'It is obvious that he has massively misinterpreted the meaning of the score he has been given,' said Professor Curtis. 'Now he is going to waste even more of the NHS's scarce resources by booking a completely unnecessary appointment with his GP to discuss a course of action to address a problem which essentially does not exist.'
A spokesperson for Prostate Cancer UK said that there was 'no clear guidance on what men should do if a genetic risk is identified – particularly in the absence of tests suitable for a prostate cancer screening programme', BBC News reported. Prostate Cancer UK said it did not recommend individuals taking commercial DNA tests to find out about their risk of the condition.