Video report by ITV News Science Correspondent Alok Jha

A new era of DNA-based medicine could offer hope to cancer patients.

In the next five years, millions of patients could have their DNA tested as genome sequencing becomes as routine as CT scans or blood tests.

The personalised testing will also benefit people with rare diseases, ending years of potential misdiagnosis and visits to different specialists.

Having access to patients' genetic blueprint can potentially make a huge difference to their diagnosis and treatment.

Tens of thousands of NHS patients have already had their DNA mapped.

But the new recommendations set out by the Government's Chief Medical Officer Dame Sally Davies aims to create a "Generation Genome".

Dame Sally said: "This technology has the potential to change medicine forever - but we need all NHS staff, patients and the public to recognise and embrace its huge potential.

"Genomic medicine has huge implications for the understanding and treatment of rare diseases, cancer and infections."

Currently, genetic testing of NHS patients in England is conducted in 25 regional laboratories and a plethora of smaller ones.

But the hope is to centralise all the labs and establish a national network providing equal access to the tests across the country.

Health Secretary Jeremy Hunt welcomed Dame Sally's report, pointing out the UK had established itself as a world leader in genomics medicine.

"Tens of thousands of patients across the country have already benefited from quicker diagnosis, precise treatment and care, and we will support the NHS to continue its relentless drive to push the boundaries of modern science to benefit even more people," he said.

DNA mapping could become as routine as a blood test. Credit: PA

What is the human genome?

Every person's genome contains 3.2 billion "letters" of genetic code, amounting to two terabytes of data.

Within the genome are 20,000 genes - stretches of DNA that provide the "software" for making proteins.

Other parts of the genome act as "dimmer switches" regulating the activity of genes.

In the case of cancer, tumour cells develop a different genome to normal cells.

For adults and children with one of the 7,000 recognised rare diseases, genome testing could lead to far speedier and more effective treatment.

By reading a patient's DNA rather than relying on the observation of often subtle symptoms, genomics testing can allow much faster diagnosis of rare diseases.