Cancer risk cut for millions with revolutionary DNA tests

The whole genome sequencing system would make tests which read a person’s entire DNA profile widely available and could be ready as early as 2024. It could save thousands of lives a year. In a study of 102 healthy patients at a GP surgery, one in four were carrying “actionable” mutations predicting illness.

These were changes to genes which increased risk of certain diseases but could be counteracted through lifestyle changes, extra monitoring or other preventive measures.

Six in 10 carried an inherited mutation in a “recessive” gene, meaning they were not affected by a condition but could pass it on to their children.

Detecting such mutations can guide healthcare decisions and enable more personalised treatment.

Study leader Professor Ros Eeles, of The Institute of Cancer Research in London, said the results could spark a “revolution in healthcare”, paving the way for testing to be rolled out to anyone who wants it in the next two to five years.

No countries are yet offering genome tests on this scale.

Prof Eeles said: “Integrating whole genome sequencing into primary care could change the way most patients and their families are managed by GPs.”

A human genome contains around 20,000 genes made up of 3.2 billion letters of DNA. Using DNA extracted from blood, tissue or skin samples, researchers looked for 566 mutations linked to disease, including 84 for cancer, 77 for heart conditions, and others affecting responses to medicines.

Around 70 per cent of those with actionable mutations would not have been identified through normal checks or family history.

Prof Eeles said the most common action taken as a result was more frequent screening for patients at risk of cancer.

One woman found to be at elevated risk of ovarian cancer chose to have her ovaries removed.

People with mutations that could be passed on to their children can be offered IVF with embryo screening.

Other possible benefits include the ability to select drugs that cause fewer side effects, or earlier prescribing of statins for people predisposed to high cholesterol.

Prof Eeles said: “It’s definitely coming. There’s a huge impetus in genome integration into healthcare in the UK.”

Health Secretary Sajid Javid said genomics was “changing the future of healthcare”.

He added: “The UK continues to lead the way in genomics expertise.”

The findings will be presented at the American Society of Clinical Oncology’s Annual Conference in Chicago.