Scientists have hailed their discovery of three genes linked to the most common form of breast cancer as 'like finding gold in Trafalgar Square'.

The finding could lead to new ways to treat and prevent hormonal breast cancer, which is diagnosed in 37,000 women in the UK each year, and accounts for four out of five of all breast tumours. The results were published today in the journal PloS Genetics.

The team was astonished because the genes were found directly next to the oestrogen receptor gene, the main driver of hormonal breast cancer. The oestrogen receptor has been intensively studied by scientists for decades and is located in one of the most well-studied areas of the genome.

Study author Dr Anita Dunbier, from the Breakthrough Breast Cancer Research Centre at The Institute of Cancer Research (ICR) in London, said: "This is a surprising discovery. We found these genes in a place we thought we knew a lot about - it is like finding gold in Trafalgar Square.

"We now have to look further at how these genes work, but the discovery could lead to possible new therapies that will benefit women with breast cancer in the future."

Dr Dunbier and her colleagues studied 104 patients with hormonal, also known as oestrogen receptor (ER) positive, breast cancer. They wanted to find the genes that were most closely linked to the oestrogen receptor.

The three genes identified were C6ORF96, C6ORF97 and C6ORF211. All three were found to be linked to the oestrogen receptor but working separately from it. As a result, their activity is unlikely to be affected by current treatments, such as tamoxifen, which target the oestrogen receptor. This could mean that they are potential targets for new drug treatments.

C6ORF211 was shown to drive the growth of tumours and the team sees this as the most likely target for new treatments. C6ORF97 was shown to be an indicator of a tumour not coming back, and also a good predictor of response to tamoxifen. Less is known about C6ORF96, but it is being researched by the team.

Professor Mitch Dowsett, who leads the team at the Breakthrough Breast Cancer Research Centre at the ICR, said: "This research is exciting because it shows that while the oestrogen receptor is the main driver of hormonal breast cancer, there are others next door to it that also appear to influence breast cancer behaviour. We now need to better understand how they work together and how we can utilise them to save lives of women with breast cancer."

Source: Institute of Cancer Research