treatment. with me is one of the chief investigators on the trial, professor richard neal, a part time gp and professor of primary care at the university of exeter. and i'm alsojoined by drjodie moffat who's head of strategic evidence and early diagnosis programme lead at cancer research uk. thank you both for being with us. first of all as one of the lead investigators on this just talk to us about the science of this. am i right in saying this is sort of dna from tumours leaking into the blood which you can then test?— from tumours leaking into the blood which you can then test? thank you, ben. which you can then test? thank you, ben- when — which you can then test? thank you, ben. when cancers _ which you can then test? thank you, ben. when cancers are _ which you can then test? thank you, ben. when cancers are present - which you can then test? thank you, ben. when cancers are present in i which you can then test? thank you, | ben. when cancers are present in the body, even if they are at an early stage they shot into the bloodstream what is called cell free dna and very tiny amounts which is really difficult to measure. what's really important is there are signals or fingerprints, scientifically called