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| Professor Melissa Southey |
Mutations in known breast cancer genes such as BRCA1 and BRCA2
are
identified in only approximately 20 per cent of women who are offered genetic
testing for familial breast cancer.
Professor Southey led a team of researchers who studied
210 people from 25 multiple case breast cancer families. They identified 24
previously unknown epigenetic changes that alter a woman’s risk of breast
cancer and can be passed down through generations without involving changes in
the DNA sequence of genes.
“For the majority of women who undergo genetic testing,
there is no explanation for their breast cancer predisposition,” said Professor
Southey, also from the Department
of Clinical Pathology at the University of Melbourne.
“This ground-breaking work is not only helpful for women
from families with many cases of breast cancer, it will improve breast cancer
risk prediction for all women, and pave the way for the development of
epigenetic therapeutics for breast cancer.”
The study, published in Nature Communications, looks at epigenetic changes called DNA methylation, where
methyl group chemicals modify DNA without changing its sequence. DNA
methylation can mimic genetic variation, predisposing a family to breast
cancer. The study is one of the first to systematically scan the genome for
places where DNA methylation is heritable, and is the first to apply this to
familial breast cancer.
University of Melbourne statistician Dr James Dowty said:
“Our methods were very successful when applied to breast cancer, and the
exciting thing is that they can be applied to many other hereditary diseases.
This work was the result of a very fruitful collaboration between molecular
biologists and statisticians, like a lot of work in modern medical research.”
Monash University and University of Melbourne research
fellow Dr Eric Joo said: “Some individuals know they come from a family with a
lot of breast cancer but do not have a mutation in a known breast cancer gene.
This study should help answer why some of those families have a lot of cancer.
It’s very exciting to be unlocking part of a big puzzle.”
Researchers from the Cancer Council Victoria’s Division
Cancer Epidemiology & Intelligence Division and The University of Utah also
contributed to the work.
