Cancer Research UK Annual Review 2011/12

Annual Review 2011/12 | 9
They also investigated how primary tumours relate
to secondary ones – the primary tumour is where
the cancer started; a secondary tumour is where it
has spread to.
The scientists revealed that no two samples were
identical – even those taken from right next to
each other in the original tumour. This discovery
showed how cancer changes and adapts as it grows
and spreads. These results help explain why it’s
difficult to predict which treatment will work, and
why some treatments become less effective later
on as the patient’s disease changes.
‘One way of looking at it is to see the tumour as
a tree,’ says Professor Swanton. ‘You have genetic
faults that are in the trunk and present in every
part of the tumour. Then you have the faults in
the branches that may differ from one part of the
tumour to the next.’
‘Identifying these widespread faults is key to
improving treatments. This is because an increasing
number of cancer drugs work by targeting genetic
faults. If you target one that’s present in one part of
the tumour and not the other, the treatment won’t
be as effective.
The next stage is to identify which faults inside each
tumour are driving the disease, as this will improve
the success of these tailored treatments.’
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