Cancer cell
Media playback is unsupported on your device

DNA mapping for thousands of cancer patients

10 December 2012 Last updated at 18:55 GMT

Up to 100,000 patients with cancer and rare diseases in England are to have their entire genetic code sequenced.

Downing Street says a database of genetic sequences and profiles will be built, so that doctors can better understand patients' illnesses and develop new treatments.

Fergus Walsh reports.