New drugs could treat more types of cancer

In collaboration with the Press Association

UK scientists have found early evidence that new drugs called PARP inhibitors could treat more types of cancer than previously thought.

The drugs block the action of an important enzyme involved in the DNA repair mechanism in cancer cells, called poly (ADP-ribose) polymerase or PARP.

In doing so, they cause the cancer cells to die, preventing the growth of tumours or even causing them to shrink, while also leaving healthy cells relatively unharmed.

Clinical trials indicate that these drugs, such as olaparib, are effective against cancers linked to BRCA mutations, including some breast and ovarian cancers.

A new study by scientists at the Breakthrough Breast Cancer Research Centre at The Institute of Cancer Research (ICR) has now revealed that they may also be effective against cancer cells with a fault in another gene - PTEN.

They discovered that cells with faulty PTEN genes - which are common in many breast, prostate, melanoma, womb and bowel cancers - are up to 25 times more sensitive to PARP inhibitors than cells with normal PTEN.

The tests were carried out on cells and mice but, if confirmed in large clinical trials, the drugs may have the potential to help thousands more cancer patients each year in the UK.

Professor Alan Ashworth, director of the Breakthrough Breast Cancer Research Centre, said: "These results are exciting because they show that PARP inhibitors are potentially a powerful targeted treatment with few side-effects which may help a broad range of cancer patients.

"Clinical trials have already shown the potential of PARP inhibitors for patients with tumours caused by faulty BRCA genes. We now need to test whether the promising results from this study can be matched in the much larger group of patients with PTEN-related tumours."

Dr Alison Ross, senior science information officer at Cancer Research UK, said: "This study, partly funded by Cancer Research UK, is exciting as it shows that PARP inhibitors could potentially offer a tailored and targeted treatment for many more cancer patients than previously anticipated.

"But the experiments were only carried out on cells grown in the lab and in mice, so we don't yet know if the same results will be seen in patients with faulty PTEN in their cancer cells."