The gene in question produces a protein called Abraxas, which links the BRCA1 protein to a complex required for repairing damaged DNA. The mutation in the Abraxas gene affects the formation of this BRCA1 complex, and its ability to enter the nucleus and bind to sites of DNA damage. This eventually leads to genetic changes that increase the risk of developing breast cancer.
Researchers at Perelman School of Medicine at the University of Pennsylvania and Oulu University Hospital's Institute of Clinical Medicine and Biocenter in Finland found this mutation in about 2.4 percent of cases of familial breast cancer. These findings, published in Science Translational Medicine, establish Abraxas as a breast cancer-susceptibility gene.
'The present results warrant investigation of Abraxas as a new cancer susceptibility gene in other populations', write the authors. According to them, this mutation may, in time, be added to a list of approximately 14 mutations associated with breast cancer which cancer-prone families can be screened for.
In a separate study also examining the BRCA1 gene, published in the Journal of Pathology, researchers have, for the first time, mapped the genetic code of two breast cancers caused by mutations in BRCA1. They found that despite both tumours being caused by a mutated BRCA1 gene, their genetic sequences were different. This, scientists argue, raises the hopes for better diagnosis and treatments for the disease.
Meanwhile, the first court case in Australia challenging Myriad Genetics over their patent on BRCA1 has begun. Myriad Genetics gained a patent in 1994, and argue that the BRCA1 mutation is qualified as an invention because the act of removing it from the body changes it 'chemically, structurally and functionally'.
David Shavin QC defended the granting of the controversial patent on BRCA1, telling the Federal Court in Sydney: 'What's in the isolated nucleic acid (taken out of the body) is not the same thing that's in the cell, and that, I think, is the key issue'. He also stated that Myriad Genetics tested 'thousands and thousands' of people 20 years ago to locate the mutation in the genome.
In 2008 Genetic Technologies, a Melbourne company that holds the Australian rights for Myriad's BRCA1 patent, wrote to eight public laboratories to inform them of these patent rights, and insisted that Genetic Technologies should perform all future tests. However, the company later backed down.
Rebecca Gilsenan, the principal lawyer representing the patient group Cancer Voices Australia, who is pressing the court to invalidate the patent, argues that BRCA1's ability to code for particular proteins, which is the key characteristic that allows it to be used as a test, is identical inside the body and out.
The court case is expected to last around a week.