Breakthrough: Common Blood Pressure Drug May Halt Deadly Breast Cancer, New Study Finds

A low-cost blood pressure medication used by millions worldwide may hold the key to slowing one of the most aggressive forms of breast cancer, according to new research from Monash University in Melbourne, Australia.

The study suggests that beta blockers—drugs typically prescribed for conditions like high blood pressure, heart failure, and anxiety—could significantly slow the progression of triple-negative breast cancer (TNBC), a deadly subtype that lacks targeted treatments.

New Clues in Cancer-Stress Link

The link between beta blockers and reduced breast cancer mortality was first observed in 2023, but until now, the biological mechanism remained unclear.

Scientists at the Monash Institute of Pharmaceutical Sciences have now pinpointed how these drugs may work: by disrupting the activity of a specific gene, HOXC12, which is triggered by stress hormones and plays a key role in tumour growth and spread.

“We’ve found that beta blockers can switch off the HOXC12 gene, which is activated by the beta-2 adrenoceptor in response to stress hormones like cortisol,” explained Professor Michelle Halls, senior author of the study. “This receptor, when triggered, increases signalling molecules like cAMP and calcium, which together drive cancer progression.”

She continued, “Our colleagues previously found that beta blockers are associated with a significant reduction in mortality in people with triple-negative breast cancer. Now we have a much better grasp on why this could be the case.”

Identifying Patients Who Could Benefit

One of the most promising aspects of the discovery is its potential to identify patients at diagnosis who are most likely to benefit from beta blocker treatment.

Terrance Lam, a pharmaceutical PhD candidate and study co-author, said:
“Our collective research strongly suggests that HOXC12 is a potential new indicator for when triple negative breast cancer patients could respond to beta blocker targeted interventions. Triple negative breast cancer is an aggressive cancer which can be especially challenging to treat, and identifying new treatment pathways is important.”

The researchers are now calling for urgent further studies to confirm whether HOXC12 levels can serve as a diagnostic tool to guide treatment decisions.

A New Use for a Familiar Drug

Beta blockers, including drugs like atenolol, work by blocking the effects of adrenaline and other stress hormones on the heart, slowing heart rate and reducing blood pressure. The new findings suggest these same mechanisms may also suppress cancer-driving pathways triggered by chronic stress.

Published in the journal Science Signalling, the study showed that patients with high HOXC12 expression were more likely to experience faster cancer progression and lower survival rates.

The Urgent Need for Better TNBC Treatments

While 85% of women diagnosed with breast cancer survive more than five years, those with triple-negative breast cancer face a much harsher prognosis.

This aggressive cancer accounts for around 15% of breast cancer cases in the UK and US. Unlike other forms, TNBC does not respond to hormone-based therapies, making treatment options limited.

Survival rates for TNBC can vary widely depending on the stage of diagnosis. While 77% of patients survive five years or more, this can drop to as low as 12% for more advanced cases—compared to around 90% survival for other breast cancer types.

The Monash researchers hope their discovery will pave the way for a cost-effective, widely accessible option for managing TNBC, potentially saving thousands of lives.

“We’re excited about the possibilities,” said Professor Halls. “But we also know that more clinical studies are urgently needed before this can become a standard part of care.”