New discovery could end chemotherapy for many patients

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A protein that helps cells stick together can help identify breast cancer victims with a high risk of the disease lethally spreading to other parts of the body, researchers revealed.

A protein that helps cells stick together can help identify breast cancer victims with a high risk of the disease lethally spreading to other parts of the body, researchers revealed.

Low levels of the protein E-cadherin appear to be the single most important factor predicting highly malignant breast cancer.

Adding the protein to other indicators has enabled doctors to distinguish patients with a 90% chance of surviving 14 years from those whose odds of remaining alive are only 44%.

The discovery could help cancer specialists decide which women should be given intense chemotherapy to halt the spread of breast cancer.

For those not at risk, chemotherapy and its serious side effects could be reduced or even withdrawn.

It is not breast cancer itself that kills but the spread of tumour cells to other sites, especially the liver and brain.

Surgeons can remove the initial tumour, while radiation is effective in treating disease that has reached nearby lymph nodes.

But chemotherapy intended to prevent distant metastases - spread of the disease around the body - is not always effective and has severe side effects.

Only 20 to 30% of women with lymph-node negative breast cancer will develop metastatic disease. But standard methods of assessing the risk of spreading breast cancer from the size and grade of tumour, the presence of oestrogen receptors and the proportion of dividing cells, are notoriously inaccurate.

The research team at the University of Chicago has spent years looking for "biomarker" proteins providing clues about spreading breast cancer.

Two other markers have already been found - low levels of a protein called nm23 and the growth of new blood microvessels feeding the tumour. Both these factors increase the risk of breast cancer spreading.

Abnormally low levels of E-cadherin, however, indicate a substantially increased risk of metastasis.

The protein is involved in cell-to-cell adhesion and also acts to suppress the invasive character of cancer cells. As cancerous cells become more invasive, they produce less E-cadherin.

The findings were published yesterday in the journal Cancer Research. Professor Samuel Hellman, the paper's co-author, said: "The additional information we can now derive from tumour biomarkers such as E-cadherin, nm23 and microvessel counts should begin to allow us to tailor therapy according to individual tumour types.

"Two thirds of node-negative patients will never develop metastases, even without chemotherapy. As we find more and more biomarkers that can predict which patients those will be, we can eliminate the unnecessary morbidity (illness) caused by treating patients who are well and perhaps increase the intensity of therapy in patients who are at high risk of metastatic disease."

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