Researchers from the National University of Singapore (NUS) have demonstrated an innovative approach for targeted breast cancer therapy using pulsed electromagnetic fields (PEMFs). The NUS team successfully reprogrammed tumour-associated macrophages (TAMs), a corrupted class of immune cells that typically promote cancer growth, into an active anti-tumour state that attacks and destroys cancer cells.

The study, led by Associate Professor Alfredo Franco-Obregón from the Department of Surgery at the NUS Yong Loo Lin School of Medicine and the NUS Institute for Health Innovation & Technology, was published in the journal Smart Medicine on 4 June 2026. This discovery builds on their previous work, where they showed that brief PEMF exposure enhances uptake of doxorubicin (DOX), a chemotherapy drug, by breast cancer cells.

PEMF therapy applies intermittent, low-intensity magnetic pulses to targeted regions of the body over a short period of time. Assoc Prof Franco-Obregón has previously explored the effect of PEMFs on muscle development and oncology. In their latest study, the NUS team demonstrated that even without chemotherapy, PEMFs completely eradicated tumours in 75 per cent of tested preclinical models after just four 30-minute sessions.

“Our study represents a major advancement in breast cancer treatment by demonstrating the potential of PEMFs as a stand-alone, drug-free therapy, offering a possible future where patients could avoid chemotherapy and its debilitating side effects,” said Assoc Prof Franco-Obregón.

Breast cancer cases are projected to rise by a third, from 2.3 million in 2023 to more than 3.5 million by 2050, while annual deaths may nearly double from 764,000 to nearly 1.4 million. Cancer treatment faces challenges such as tumour heterogeneity, drug resistance, and treatment-related toxicities. Approaches targeting TAMs also faced difficulties such as off-target effects. The growing burden underscores the urgent need for innovative therapies to improve patient outcomes and save lives.

From cancer’s friends to foes

Breast cancer occurs when cells in the breast mutate and grow uncontrollably, forming a solid tumour. These cancer cells recruit and hijack nearby immune cells, corrupting them to protect the tumour, accelerate tumour growth, and encourage the spread of cancer (metastasis). Prominent among these recruited immune cells are TAMs, which are abundant in nearly all solid tumours.

There are two primary types of macrophages, M1 and M2. M1 macrophages are pro-inflammatory – the “soldiers” that eliminate threats like bacteria and viruses. M2 macrophages are anti-inflammatory – the “medics” that orchestrate wound healing and tissue repair once threats are cleared. Cancer cells corrupt most TAMs into adopting the M2 “medic” state, suppressing immune attacks against the tumour while facilitating tumour growth and metastasis.

The key to this macrophage reprogramming lies in a protein called TRPC1 (Transient Receptor Potential Canonical 1), which regulates the M1 state. Crucially, TRPC1 also allows cells to sense and respond to magnetic fields. In their experiments, the NUS team confirmed that a brief 10-minute exposure to PEMFs activated TRPC1 channels on M2-like TAMs, setting off a signalling cascade that converted them to the M1 state – essentially turning TAMs from helpful “medics” to aggressive cancer-killing “soldiers”. These activated TAMs then selectively target cancer cells while sparing healthy tissue. Furthermore, the same magnetic signature disrupts cancer's ability to hijack TAMs, altering the TAM-cancer communication loop in both directions.

“We have identified a molecular “switch”, the specific cell signalling pathway that allows us to reprogram TAMs. Once reprogrammed, these immune cells actively hunt and devour cancer cells, obliterating the tumour,” said Assoc Prof Franco-Obregón. “With the non-invasive and targeted nature of PEMF therapy, we hope to provide patients an effective and safe alternative treatment, with fewer undesirable side effects.”

Pulses of hope for cancer patients

Assoc Prof Franco-Obregón shared that the same PEMF device used in this study has just successfully completed Phase 1 clinical trials, demonstrating its safety in humans. The team is now seeking partners to conduct Phase 2 efficacy trials to evaluate how well the PEMF treatment works in patients and to further advance its development towards clinical use.

“Since we previously showed that PEMFs selectively increased the uptake of DOX in breast cancer cells, we will be evaluating if our PEMF immunotherapy can work synergistically with chemotherapy for better results,” added Assoc Prof Franco-Obregón. “As the immune cells we reprogram are commonly found in most solid tumours, we are optimistic that our PEMF therapy could potentially be a complementary treatment for other cancers beyond breast cancer.”