The damage chemotherapy can cause to the healthy cells around tumours - the so-called 'tumour microenvironment' - could help cancer to develop resistance to treatment, according to a US study.

The knowledge could be used to develop ways to overcome drug resistance and improve cure rates.

Scientists from the Fred Hutchinson Cancer Research Center in Seattle discovered that chemotherapy can damage the DNA in non-cancer cells called fibroblasts, which then causes the production of a molecule that encourages prostate tumours to grow.

Fibroblasts usually help to ensure connective tissue in the body is intact and have a vital role in wound healing.

But the researchers found that chemotherapy can cause fibroblasts to increase production of a molecule called WNT16B by 30-fold in tissues surrounding a tumour.

This then helps cancer cells to grow, invade neighbouring cells and resist chemotherapy, the research team said.

Commenting on the finding, Professor Fran Balkwill, a Cancer Research UK expert on the microenvironment, 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 in and 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.

The research team said its study highlights the fact that, even though cancer treatments are becoming increasingly targeted, the tumour "neighbourhood" can still play a key part in the therapy's success.

The study is published in the journal Nature Medicine.

Source: CRUK