Taking a sample from just one part of a tumour may not give a full picture of its ‘genetic landscape’, according to a landmark study published in the New England Journal of Medicine.

The findings could help explain why attempts at using single biopsies to identify biomarkers to which personalised cancer treatments can be targeted have not been more successful - but also points to a way forward.

Cancer Research UK scientists carried out the first ever genome-wide analysis of the genetic variation between different regions of the same tumour using kidney cancer samples. They found that the majority, around two thirds of gene faults, were not shared across other biopsies from the same tumour.

Lead author Professor Charles Swanton, based at Cancer Research UK’s London Research Institute and the UCL Cancer Institute, said: “We’ve known for some time that tumours are a ‘patchwork’ of faults, but this is the first time we’ve been able to use cutting-edge genome sequencing technology to map out the genetic landscape of a tumour in such exquisite detail.

“This has revealed an extraordinary amount of diversity, with more differences between biopsies from the same tumour at the genetic level than there are similarities. The next step will be to understand what's driving this diversity in different cancers and identify key driver mutations that are common throughout all parts of a tumour."

Source: CRUK