Genetic similarities found between ovarian and breast cancers

Scientists have found molecular similarities between a subtype of
breast cancer and a hard-to-treat form of ovarian cancer. The researchers analysed
over 800 tumour samples, characterising their DNA and protein expression patterns.
These results provide greater detail into what goes wrong in breast cancer.

Professor Carlos Caldas, from Cancer Research UK, who was not
involved in the study said: 'This comprehensive new analysis of 800
breast tumours is a welcome addition to the wealth of new information about the
underlying biology of breast cancer, and will be a precious and valuable resource
for cancer researchers'.

Researchers, based at National Cancer Institute (NCI) and
the National Human Genome Research Institute (NHGRI) in the USA, studied over 800 tumours in
detail, looking at DNA, mRNA and protein expression patterns. In doing
so, researchers found the breast cancers fell into four main groups; HER2-enriched,
luminal A, luminal B and basal-like.

Further study showed the basal-like subtype of breast cancer
had similarities, at the level of the genome, with serous ovarian cancer. Similar
genomic mutations and frequencies of mutation were found between both forms of
cancer.

Basal-like breast cancer is often referred to as triple
negative because these tumours generally test negative for three receptors normally
associated with breast cancer. This makes them resistant to conventional
treatment methods that target these receptors.

Professor Harold Varmus, of the NCI, said: 'The
molecular similarity of one of the principal subtypes of breast cancer to that
found in ovarian cancer gives us additional leverage to compare treatments and
outcomes across these two cancers. This treasure trove of genetic information
will need to be examined in great detail to identify how we can use it
functionally and clinically'.

It is expected that new findings will emerge from this
comprehensive study. Eric Greene, director of the NHGRI, comment: 'The data generated by this programme comprise a
vast resource that investigators will be analysing for years to come. The
resource of information about breast cancer genomes will undoubtedly fuel
myriad discoveries by the cancer research community'.