* Breast cancer killed more than 508,000 women in 2011
* Some gene mutations increase risk of developing disease
* PALB2 mutation almost as important as BRCA1/2 genes
By Kate Kelland
LONDON, Aug 6 Women with mutations in a gene
called PALB2 have a one in three chance of developing breast
cancer by age 70, according to research that suggests PALB2 is
almost as important a risk factor as BRCA1 or BRCA2 mutations.
BRCA1 and BRCA2 are widely known as breast cancer risk
genes. Women with a mutation in one or both often decide to have
their breasts removed so they do not develop the disease.
Last year, actress Angelina Jolie went public with her
decision to undergo prophylactic mastectomy after she tested
positive for a BRCA mutation. Mutations in the same genes also
increase the risk of ovarian cancer.
In a study published in the New England Journal of Medicine
on Wednesday, researchers reported they had analysed data from
154 families without BRCA1 or BRCA2 mutations, which included
362 family members with PALB2 gene mutations.
They found that women who carried rare mutations in PALB2
had on average a 35 percent chance of developing breast cancer
by the time they were 70 years old.
But the risks were highly dependent on family history of
breast cancer, the researches said. Those with more relatives
affected by breast cancer were at higher risk.
"We're learning all the time about the different factors
that may influence a woman's chances of developing breast
cancer," said Peter Johnson, chief clinician at the charity
Cancer Research UK, which part-funded the study.
"This particular mutation doesn't make people certain to
develop cancer, but it's another piece of information to help
women make proper informed choices about how they may help to
minimise their own risk."
Breast cancer is the most common cancer in women worldwide.
The World Health Organisation estimates it killed more than
508,000 women in 2011.
Marc Tischkowitz from the department of medical genetics at
Britain's University of Cambridge, who led the study, said that
since the BRCA1 and BRCA2 mutations were discovered in the
mid-1990s, no other genes of similar importance have been
identified. This new finding, however, makes PALB2 a potential
candidate to be the third most important genetic risk factor for
"Now that we have identified this gene, we are in a position
to provide genetic counselling and advice," he said in a
statement about the research. "If a woman is found to carry this
mutation, we would recommend additional surveillance, such as
MRI breast screening."
The researchers at Addenbrooke's Hospital in Cambridge have
developed a clinical test for PALB2 which they said will become
part of their service on Britain's taxpayer-funded National
Health Service. Clinical testing for PALB2 is also available in
certain other diagnostic laboratories worldwide, they said.
The scientists said there is evidence that cells carrying
the PALB2 mutation are sensitive to a new class of drugs known
as PARP inhibitors that are undergoing trials in BRCA1- and
BRAC2-related breast cancers. The drugs also may work in
PALB2-related breast cancer, they said.
The Anglo-Swedish drugmaker AstraZeneca is
developing a PARP inhibitor drug called olaparib, which is going
through clinical trials.
(Editing by Larry King)