Scientists identify potential risk factors for aggressive form of breast cancer

Some household detergents, antiseptics and insecticides are potential environmental risk factors and new targets for treating an aggressive form of breast cancer, scientists say.

According to new data, exposure to common everyday chemicals may increase the risk of developing a difficult-to-treat type of breast cancer.

However, experts say that while the study has no clinical or public health implications, it identifies areas for new research.

Triple negative breast cancer (TNBC) is an aggressive form that particularly affects younger people and makes up 10-20% of all breast cancer diagnoses.

While curable if caught early, TNBC is resistant to hormone treatments and newer targeted therapies used to treat other types of breast cancer.

It is therefore treated with surgery, radiotherapy and chemotherapy.

Researchers say there is a better need to understand the biology of this aggressive form of breast cancer in order to develop new therapies, improve quality of life, and identify how to reduce the risk of developing it.

Women with other types of breast cancer that are hormone receptor positive are treated with hormonal therapies which target oestrogen and progesterone receptors – two of 48 nuclear receptors (NRs).

It is known that many NRs are altered in breast cancer.

This means they can be potential drivers of breast cancer development and possible new therapeutic targets.

The receptors act as environmental sensors, working together to control different aspects of how breast and other tissues work.

But how environmental chemicals change their activity is not well known, especially in the context of TNBC.

Dr Laura Matthews and Professor Chris Twelves from the University of Leeds, with Professor Valerie Speirs from the University of Aberdeen led a study funded by charity Breast Cancer UK.

They mapped the entire NR superfamily in 68 breast cancer samples and from normal breast tissue, to identify common alterations in NR activity.

Comparing their findings with those from other studies to identify NRs associated specifically with TNB, they were able to predict which drugs or environmental chemicals are more likely to generate the distinct NR profiles associated with TNBC.

In the abstract presented at the Society for Endocrinology annual conference in Brighton, they said these include disinfectants, insecticides, dietary fats and industrial pollutants.

Dr Matthews said: “Identifying these NR networks, and ways they might be controlled in patients with TNBC, is really important.

“We are now investigating how the environmental chemicals change the behaviour of normal breast cells so we can understand how they might drive cancer development.

“We are also testing whether using drug combinations that target multiple NRs at the same time might prevent or be an effective treatment for TNBC.

“Our goal is to reduce the number of people that develop breast cancer, and guide new therapies, so that more people can live beyond breast cancer.”

Dr Mangesh Thorat, deputy director of the Barts Clinical Trials Unit at the Centre for Cancer Prevention at Queen Mary University of London, said: “While this preliminary study does not at the moment have any clinical or public health implications, it identifies new avenues for research into causes of a type of breast cancer – triple negative breast cancer – and the biomarkers identified could be clinically useful in treatment of this cancer if appropriately validated in further studies.”

Justin Stebbing, National Institute for Health Research research professor of cancer medicine and medical oncology, Imperial College London, said: “This study opens up new avenues for research.

“However, for now there is no link between household antiseptics or chemicals to breast cancer.”