A new test that identifies seven distinct types of breast cancer offers new hope to women with the disease, say scientists.
The tumour sample test could be available within two years and is expected to lead to more personalised treatments.
Identifying more biomarkers will help doctors tailor therapy plans that better suit their patients, avoiding over or under treatment.
Currently just two proteins are routinely identified in breast cancer cells. One is the oestrogen receptor (ER) that makes a tumour hormone-sensitive. The other is HER2, which is responsive to the breast cancer drug Herceptin.
Scientists funded by the Breast Cancer Campaign looked for signature biomarkers in 1,073 tumour samples from the charity's tissue bank. They found that 93% fitted perfectly into one of seven classes. Another 7% had mixed characteristics and were harder to categorise.
Further verification of the seven cancer types was then made using another 28 tumour samples.
The seven classes are defined by different combinations and levels of 10 proteins found in breast cancer cells. These include ER and HER2, but also others not currently tested, such as p53, cytokeratins, HER3 and HER4.
Each cancer type has a different effect on patient survival, according to the scientists whose findings are reported in the British Journal of Cancer.
Lead researcher Dr Andy Green, from the University of Nottingham, said: "With an increasing number of treatment options available for breast cancer patients, decision making regarding the choice of the most appropriate treatment method is becoming increasingly complex. Improvements in care and outcome for patients with breast cancer will involve improved targeting of effective therapies to appropriate patients.
"Equally important should be improvement in parallel strategies to avoid unnecessary or inappropriate treatment and side effects."
The technology needed to measure the proteins in tumour samples already exists in most pathology laboratories across the UK, he said.
Last year researchers categorised 10 different forms of breast cancer based on their underlying gene defects. But they can only be identified using sophisticated genetic profiling, making this form of test for patients costly and impractical.
In contrast, the seven cancer test could be ready for use in the clinic in as little as two years, it is claimed.
The university spin-out company Nottingham Prognostics Limited has integrated the biomarkers into its existing NPI test already used to assess information about tumour size, spread and grade.
Baroness Delyth Morgan, chief executive of the Breast Cancer Campaign, said: "The days of one size fits all treatment are well and truly in the past. We need to ensure the life-saving and life-extending treatments we already have in the clinic are used more effectively - directing the right treatments to those who will benefit, and sparing others from unnecessary side effects, so that by 2050 we can achieve our ambition to overcome breast cancer.
"This new test could be a realistic step towards making the holy grail of personalised medicine a reality, offering hope to the 50,000 women diagnosed with breast cancer in the UK every year."
She added: " We look forward to seeing the results from external validation studies using cases from the UK, USA and Europe and hope that a subsequent feasibility study will allow this exciting work to be fast-tracked into the clinic."