Scientists in the UK and Canada have discovered a new oncogene - the genes responsible for cell multiplication - that plays a role in the development of a particularly aggressive form of breast cancer.

In what is believed to be the first discovery of an oncogene in the past five years, Professor Carlos Caldas from the Cambridge Research Institute and his research team hope their investigation into the role of the gene will lead to improvements in breast cancer detection, monitoring, and eventually, treatment.

'It's only with the technology we have today that we've been able to narrow down the search sufficiently to pinpoint the gene responsible', said Professor Caldas.

The gene, known as ZNF703, was identified in a region of DNA on chromosome eight, which was first recognised as a potential harbour for breast cancer oncogenes around 20 years ago. Until now, however, scientists were unable to confirm the existence of any oncogenes suspected of being present in the molecular region.

But using a technique known as microarray analysis, the team compared the activity of thousands of genes in over 1,100 samples from human tumors and healthy tissue. The method allows scientists to identify which genes are 'turned off', and which are 'activated'.

As oncogenes 'accelerate' the multiplication of cells when needed, Professor Caldas looked for genes which were more overactive in the cancer tissue relative to the healthy samples. When oncogenes become overactive, they have been likened to a stuck car accelerator, causing cells to multiply uncontrollably leading to cancer.

The researchers studied the activity of individual genes in a large number of samples to narrow down those most commonly overactive gene, eventually isolating ZNF703 which also displayed the most oncogene-like behaviour. Samples from two breast cancer patients showed ZNF703 as the only overactive gene, further indicating the discovery of an oncogene.

'Hopefully this will lead to more effective cancer treatments in the future', said Dr Lesley Walker, director of cancer information at Cancer Research UK.

The gene is attractive as a target for future anti-cancer drugs as it is strongly linked to tissue samples from patients with a type of breast cancer known as Luminal B, which is strongly resistant to existing hormone therapies such as Tamoxifen.

The breast cancer drug Herceptin was developed in response to the discovery of the oncogene Human Epidermal growth factor Receptor 2 (Her2) and it is hoped this discovery may lead to other tailor made treatments.

The study was published in the journal EMBO Molecular Medicine