Early days, but Korean scientists have demonstrated a new process in bowel cancer cells and living laboratory fish.
The magnetic therapy involves creating tiny iron nanoparticles, which are attached to antibodies that can bind to "receptor" molecules on tumour cells.
When the magnetic field is applied, the molecules cluster together, automatically triggering the "death signal" that sets off cancer cell death (apoptosis).
Details of the research, led by Professor Jinwoo Cheon, from Yonsei University in Seoul, Korea, appear in the journal Nature Materials.