Research out of Dundee University has shed new light on how ovarian cancer becomes resistant to certain treatments.

The study, publishing in the British Journal of Cancer, found that ABCB1, a gene known to play a key role in the development of resistance to the chemotherapy drug paclitaxel in ovarian cancer patients, also causes resistance to other therapies.

When researchers treated chemotherapy-resistant ovarian cancer cells with certain PARP inhibitors, including olaparib (AstraZeneca's Lynparza) and rucaparib, they discovered that these cells used ABCB1 in the same way to survive the treatment. They also discovered that when the same cancer cells were treated with two other types of PARP inhibitors, veliparib and AZD2461, no resistance developed.

"Our study shows an important resistance mechanism which is common to drugs used routinely in the clinic and to new drugs which are being tested in clinical trials," noted lead researcher Dr Gillian Smith. "Increasing our understanding of resistance mechanisms will allow us to develop tests to spot drug resistance more easily and to make sure patients are given the most appropriate drugs," and "understanding the biology of drug resistant cancers could also lead to the development of new treatments that block cancer's escape, making them susceptible to therapy again."

Nell Barrie, senior science information manager at Cancer Research UK, said the findings show, for the first time, "that the same mechanism that causes ovarian cancer to become resistant to paclitaxel also applies to some PARP inhibitors and other chemotherapy treatments".

"Further studies are now needed in patients to see whether some treatments will perform better than others at helping to control ovarian cancer," she noted.