A faulty gene linked to bowel cancer interacts with dietary iron to significantly increase the risk of developing the
disease, research on mice suggests.
Professor Owen Sansom, deputy director of the Cancer
Research UK Institute for Cancer Research in Glasgow, who led the study, said
that the gene in question, called APC, 'is faulty in around eight out of ten bowel cancers but until now we haven't known how this causes the disease'.
Bowel cancer is the third most common cancer in the UK, with 41,000
cases diagnosed each year. Around 16,000 of people die from the disease
The scientists tested mice with and without the faulty gene and
fed one group a diet high in iron and another no iron. They found that the iron
reacted with the non-working gene to drastically increase the likelihood of
developing bowel cancer. The risk was two to three times higher than those mice
that had a working APC gene.
Writing in the journal Cell Reports, the researchers say
that the faulty APC gene allows iron to build up in the cells lining the gut.
This activates a key cancer signalling pathway called wnt, causing cells to
grow out of control.
The study may explain why diets high in red meat, which
contains a lot of iron, are associated with bowel cancer. But Professor Sansom commented that the study
'shows that even very high levels of iron in the diet don't cause cancer by
itself, but rely on the APC gene'. The
mice with the faulty APC gene that were fed with a low iron diet did not
develop the disease as the faulty cells were killed.
Co-author Dr Chris
Tselepis, a Cancer Research UK scientist at the University of
Birmingham, said: 'Our results also suggest that iron could be raising the risk
of bowel cancer by increasing the number of cells in the bowel with APC faults.
The more of these cells in the bowel, the greater the chance that one of these
will become a starting point for cancer'.
He added that the team was 'planning to develop
treatments that reduce the amount of iron in the bowel and so could lower the
risk of developing bowel cancer'.