Chemotherapy can actually boost the growth of cancer cells, making the disease harder to fight. Some anti-cancer drugs have been proven to damage the DNA of normal tissue, causing it to secrete chemicals and resist treatment.
But far from being seen as a negative development in the battle against cancer, scientists hope the discovery will help enhance treatment.
‘The next step is to find ways to target these resistance mechanisms to make chemotherapy more effective,’ said Prof Fran Balkwill of Cancer Research UK.
‘Cancer treatments don’t just affect cancer cells but can also target cells in and around tumours.
‘Sometimes this can be good – for instance, chemotherapy can stimulate surrounding healthy immune cells to attack tumours.
‘But this work confirms that healthy cells surrounding tumours can also make them resistant to treatment.’
Dr Peter Nelson, who carried out the research at the Fred Hutchinson Cancer Research Centre in Seattle, explained: ‘Cancer cells inside the body live in a very complex environment or neighbourhood.
‘Where the tumour cell resides and who its neighbours are influence its response to therapy.’
The research, which was published in the online journal Nature Medicine, looked at cancer cells taken from prostate, breast and ovarian cancer patients who had been receiving chemotherapy.
Blocking the treatment response of fibroblasts – a type of normal, non-cancerous cell found near tumours – could be one way to improve the effectiveness of chemotherapy.