The conference will hear about advances in cancer cell research

Dietary carotenoids are the pigments in yellow, red and green vegetables.

Researchers have found that they could be used to stop the growth of tumours by restoring communication between cells.

The conference in Glasgow will hear how keeping cells in communication with each other may also stop cancer from developing in the first place.

Dr John Bertram of the University of Hawaii's cancer research centre is set to tell a Biochemical Society conference that dietary carotenoids increased the activity of a molecule called connexin 43.

Connexin 43 may be a potential new target for cancer treatment Dr John Bertram

This molecule formed small channels between cells, enabling the exchange of nutrients and signals needed for normal cell growth.

Dr Bertram was set to tell the conference at the SECC that most tumour cells lose the ability to communicate and become isolated from their normal neighbours.

But when normal mouse cells were treated with carotenoids, cell communication was improved and cancer-causing chemicals did not lead to the formation of cancer.

'Preventable' cancer

And when three different types of human tumours were treated with carotenoids, communication between cells was restored and the cells behaved more normally, both in cultures and when grown in laboratory animals.

The activity of the connexin 43 molecules could also be improved by another substance, retinoids, which were derived from vitamin A.

"Connexin 43 may be a potential new target for cancer treatment," Dr Bertram said.

He believes that maintaining efficient communication between cells could also be how carotenoids and retinoids stopped cancers forming in the first place.

The conference was set to hear studies have shown up to 70% of human cancer is preventable and that 40% of this could be attributed to diet.

Dr Bertram said that although carotenoids are available as tablets, people should instead eat carotenoid-rich fruit and vegetables.

The conference is also due to hear from Dr Graeme Laurie from Edinburgh University.

Research problems

Dr Laurie is concerned that "deeply flawed" European patent laws could discourage the development of stem cell technologies.

He said that an EU directive on biotechnology allowed patents to be denied on moral grounds.

And although the provisions did not mention stem cell research, independent guidelines cast "a heavy shadow" over the prospect of patenting stem cell technologies.

Dr Laurie said: "The irony, however, is that this will not stop research on embryonic stem cells in Europe."

"It just means that stem cell technologies developed here are not patentable.

"The result is that such research is likely to move outside Europe, either to the US or elsewhere."