New method for detecting breast cancer uses magnetic particles and SQUID
28 October 2011
A new and potentially more sensitive method of detecting breast cancer has been developed that uses tumour-targeting magnetic iron oxide particles and superconducting quantum interference device (SQUID) sensors.
In a lab situation it was 100x more sensitive than a mammographic X-ray. Mammography can detect very small tumors, but fails to find 10-25% of tumors and is unable to distinguish between benign and malignant disease.
A team of researchers from the University of New Mexico School of Medicine and Cancer Research and Treatment Center, Senior Scientific, LLC, and the Center for Integrated Nanotechnologies facility at Sandia National Laboratories created tiny probes that target cancer cells by attaching iron-oxide magnetic particles to antibodies against HER-2, a protein overexpressed in 30% of breast cancer cases.
Uing these tiny protein-iron particles the team was able to distinguish between cells with HER-2 and those without, and were able to find HER-2 cancer cells in biopsies from mice. In their final test the team used a synthetic breast to determine the potential sensitivity of their system.
Dr Helen Hathaway explained, “We were able to accurately pinpoint one million cells at a depth of 4.5 cm. This is about 1000x fewer cells than the size at which a tumor can be felt in the breast and 100x more sensitive than mammographic X-ray imaging. While we do not expect the same level of nanoparticle uptake in the clinic, our system has an advantage in that dense breast tissue, which can mask traditional mammography results, is transparent to the low-frequency magnetic fields detected by the SQUID sensors.”
Future refining of the system could allow not only tumor to be found but to be classified according to protein expression (rather than waiting for biopsy results). This in turn could be used to predict disease progression and refine treatment plans and so improve patient survival.
Hathaway HJ, et al. Detection of breast cancer cells using targeted magnetic nanoparticles and ultra-sensitive magnetic field sensors, Breast Cancer Research (in press).