Breast cells naturally take up zinc, but when they turn cancerous a faulty biological pathway causes them to hold on to higher amounts of the metal than normal.A metal detecting blood test could one day form part of a screening programme for early signs of breast cancer.
Scientists have discovered that breast cancer cells contain high concentrations of zinc consisting of ‘light’ atomic variants, or isotopes.
They expect to find a corresponding isotopic signature in the blood that would provide a simple way to detect breast cancer before the formation of noticeable tumours.
The UK team borrowed techniques normally used by earth scientists to study climate change and planetary formation to investigate how the human body processes metals.
Lead researcher Fiona Larner, from Oxford University’s Department of Earth Sciences, said: “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.
“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 the shorter term it was likely to be reserved for high-risk women with inherited breast cancer genes, such as BRCA1 or 2.
Breast cells naturally take up zinc, but when they turn cancerous a faulty biological pathway causes them to hold on to higher amounts of the metal than normal.
The cancer cells also show a preference for ‘light’ isotopes of zinc, the research showed. Isotopes are variants of chemical elements that have different numbers of neutron particles in their nuclei. A higher ratio of ‘light’ zinc in breast cancer cells should result in correspondingly more of the remaining heavier isotopes in the blood. Larner’s team is actively looking for these isotopes in white blood cells and blood proteins.
New insights into ways to detect breast cancer are exciting
“We’ve done the first half of the research,” said Larner. “Finding a blood biomarker would be a lot more useful for diagnosis.”
Other trace metals may leave different isotopic signatures that could be used to spot other cancers, the scientists believe.
Larner added: “The hope is that this research is the beginning of a whole new approach. Understanding how different cancers alter different trace metals within the body could enable us to develop both new diagnostic tools and new treatments that could lead to a two-pronged attack on many cancers.
“Further research is already under way to see what changes in other metals may be caused by other cancers.”
The pilot study, published in the Royal Society of Chemistry journal Metallomics, analysed zinc in blood and tissue samples from a number of breasts cancer patients and healthy volunteers.
Zinc is an essential trace element that has a number of vital functions in the body. It is important to the immune system, essential for cell division, and helps to maintain the structure of cells and organs. Many people take zinc supplements, but Larner said this had no bearing on their risk of breast cancer. “Your body needs zinc − that’s why the breast cells store it, because we don’t get enough in our diet,” she said.
Matthew Lam, senior research officer at Breakthrough Breast Cancer, said: “New insights into ways to detect breast cancer are exciting as the earlier the disease is discovered the better the chance of survival.
“We know that changes in zinc occur in breast cancer tissue compared to healthy tissue and this study shows it may be possible to detect these changes using a technique more familiar to earth and planetary science.
“However, this research is in a very early stage and much more research is required to not only support but also build on these results to find out if detecting changes in zinc can be used to diagnose breast cancer early.”