Chemotherapy can backfire by 'encouraging cancer growth'
Chemotherapy found to affect healthy cells surrounding cancer cells

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UPDATED:

09:11 GMT, 6 August 2012

Chemotherapy can backfire by encouraging healthy body cells around the tumour to produce a protein that helps the cancer to resist treatment, research has shown.

The surprise discovery suggests that some forms of cancer treatment can actually make the disease tougher to tackle.

Almost all solid tumour cancers, such as
those affecting the breast, prostate, lung and bowel, ultimately stop
responding to chemotherapy.

Blocking the response of a non-cancerous cell found near tumours could be one way of improving chemotherapy

Treatment: Blocking the response of a non-cancerous cell found near tumours could be one way of improving chemotherapy

Scientists believe the treatment could affect healthy connective tissue cells called fibroblasts.

In lab experiments they found the cancer drug caused DNA damage which made fibroblasts pump out 30 times more of a protein than normal. This protein encouraged prostate tumours to grow and spread into surrounding tissue, as well as to resist chemotherapy.

'Cancer cells inside the body live in a very complex environment or neighbourhood,' said lead scientist Dr Peter Nelson, from the Fred Hutchinson Cancer Research Centre in Seattle, U.S.

'Where the tumour cell resides and who its neighbours are influence its response and resistance to therapy.'

Blocking the treatment response of fibroblasts could improve the effectiveness of chemotherapy, say the scientists whose findings are reported in the journal Nature Medicine.

The team examined cancer cells from prostate, breast and ovarian cancer patients who had been treated with chemotherapy.

Professor Fran Balkwill, from Cancer Research UK expert, said that this finding ties in with other research that has shown that 'cancer treatments don't just affect cancer cells, but can also target cells around tumours'.

This effect can sometimes be a positive one, Professor Balkwill said, as is the case when chemotherapy stimulates healthy immune cells to attack tumours nearby.

'But this work confirms that healthy cells surrounding the tumour can also help the tumour to become resistant to treatment. The next step is to find ways to target these resistance mechanisms to help make chemotherapy more effective,' Professor Balkwill added.