‘Gene switch’ key to treating killer cancers: Aussie scientists

Scientists may be able to turn lethal breast cancers into treatable types with the flick of a gene “switch”.

Research

Australian scientists may have found a way to convert lethal breast cancers into treatable types with the flick of a gene “switch”.

A Sydney research team has identified a gene that triggers the growth of many “triple-­negative” breast cancers, considered the most mysterious and ­aggressive form of the disease.

The study found that when the gene was blocked, proteins known as oestrogen receptors were activated, potentially ­allowing doctors to suppress the cancer with existing drugs. The study has also identified two types of triple-negative cancers, opening the way to targeted treatments.

The research, published in the journal Nature Communications, is the latest in a string of new findings about triple-­negative cancers — so called because the cancerous cells test negative to three types of molecules implicated in most breast tumours.

“They’re defined by the ­absence of what we know,” said senior author Alex Swarbrick of the Garvan Institute of Medical Research. “That’s why there’s been intense effort over the last few years focusing on these cancers. They make up something like 15 per cent of diagnoses, but account for about 30 per cent of deaths. (Sufferers) are often significantly younger than other breast cancer patients, so they’re stealing even more years of life.

“And all we have to treat them is surgery, radiotherapy and chemotherapy, which is what we’ve had for decades.”

The researchers studied breast tissue in mice, analysed specimens of human tumours, and grew “experimental models” of triple-negative cancers. They found high levels of the gene, called ID4, in about half of the tumours. “And these cancers have a particularly poor prognosis,” Dr Swarbrick said.

He said it could take a decade or more to develop a human drug capable of switching off ID4, if that proved to be a viable strategy. But the findings will generate immediate benefits, with researchers now able to reanalyse past clinical trials armed with new knowledge.

“The ID4 status of a triple negative breast cancer may predict whether that woman should or should not be given therapy X, Y or Z,” Dr Swarbrick said. “For example, the choice of chemotherapies that oncologists use to treat triple-negative breast cancer is often an educated guess.

“It’s possible that by now identifying these two biological groups within triple-negative breast cancer, we’ll be better at personalising who should receive which chemotherapy. Up until now, we’ve been lumping all triple-negatives together.”