Metal Test Could Improve Breast Cancer Diagnostics
By Chuck Seegert, Ph.D.
A simple blood test that detects zinc in the body could help in the early diagnosis of breast cancer. By using zinc isotope analysis, a technique usually used to study planet formation, Oxford University researchers looked at how metals are processed in the human body.
Detecting cancer early is one of the primary goals in the field of oncology. Finding tumors earlier is nearly always the best bet for successful treatment, which is one reason why the study of biomarkers continues to increase substantially.
Recently, a potential biomarker for breast cancer was discovered from an unlikely source — the earth sciences, according to a recent press release from the University of Oxford. The method studies the composition of zinc isotopes using a technique that is more than 100 times more sensitive to isotope change than anything in the clinic today.
Historically, it was known that zinc levels were elevated in breast cancer tissues, but what caused this was unknown.
“It has been known for over a decade that breast cancer tissues contain high concentrations of zinc but the exact molecular mechanisms that might cause this have remained a mystery,” said lead researcher Dr. Fiona Larner, a professor in Oxford University's Department of Earth Sciences, according to the press release. “Our work shows that techniques commonly used in earth sciences can help us to understand not only how zinc is used by tumour cells but also how breast cancer can lead to changes in zinc in an individual's blood – holding out the promise of an easily-detectable biomarker of early breast cancer.”
In a world-first study, the researchers identified how cancer cells process zinc, according to a study published by the team in the journal Metallomics. The isotopic analysis showed that the composition of zinc in cancer cells was significantly lighter than the isotopic composition of zinc in the blood, serum, and breast tissue of a healthy person.
The upshot of the team’s analysis is that tumors appear to preferentially choose which zinc isotope it uses, according to the study. This may be caused by a sulfur-rich metallothionein rather than other zinc-specific proteins. This trend was confirmed by studying 10 patients — five normal patients that acted as controls and five patients with breast cancer.
In addition to identifying what may be an early biomarker for breast cancer, the research may have promise in developing novel treatments for the disease. Knowing how the tumor cells use zinc could help in understanding the pathology behind the disease and potentially aid in the development of cures.