A new study suggests it may be possible to detect the early signs of breast cancer with a simple blood test that measures changes in the zinc in our bodies.
The study, led by scientists from the University of Oxford in the UK, is the first to show that measurable changes in zinc isotope composition can be detected in breast tissue and could be used as a biomarker for early breast cancer. The findings are reported this month in the journal Metallomics.
Breast cancers that are found after they start to cause symptoms – for example, a new lump or swelling, or changes in nipple shape and texture – are usually larger and more likely to have started spreading than breast cancers found before symptoms emerge.
The size of a breast tumor and how far it has spread are two of the most important factors in predicting the success of treatment and the longer-term outlook for the patient.
Biomarkers for early breast cancer could save lives
Widespread use of screening mammograms has increased the number of breast cancers found before symptoms emerge, but they also miss many. Early diagnostic biomarkers for breast cancer could help save thousands of lives.
In this latest study, the researchers applied techniques normally used by earth scientists to understand climate change and the birth of planets, to investigate how the body processes metals.
The techniques – which are over 100 times more sensitive to changes in metal composition than any clinical lab instruments – measure the levels of trace metals in terms of the relative proportions of their different isotopic forms.
Isotopes are different forms of the same element that vary only in terms of the number of neutrons in their atomic nuclei.
Tumor cells cause subtle changes in zinc composition
For the study, the team analyzed the composition of zinc in the blood and blood serum of 10 people – five patients with breast cancer and five healthy controls. They also studied samples of healthy breast tissue from both groups and samples of breast cancer tumors from the breast cancer patients.
They found that the breast cancer tumors had a significantly lighter zinc isotopic composition than the blood, serum, and healthy breast tissue of both the breast cancer patients and the healthy controls.
The team suggests the subtle differences in zinc composition occur because tumor cells process the metal differently to normal cells. They also found similar changes in copper in one of the breast cancer patients.
Lead investigator Dr. Fiona Larner, of Oxford’s Department of Earth Sciences, says they hope their research “is the beginning of a whole new approach” to early diagnosis.
According to Dr. Larner, scientists have known for over 10 years that breast cancer tissue carries high levels of zinc, but the underlying processes that cause this are not well understood.
These new findings “show that techniques commonly used in earth sciences can help us to understand not only how zinc is used by tumor cells but also how breast cancer can lead to changes in zinc in an individual’s blood,” she says
Zinc could be an ‘easily detectable biomarker of early breast cancer’
The study results carry the “promise of an easily detectable biomarker of early breast cancer,” adds Dr. Larner.
The team also discovered that sulfur-rich proteins play a key role in how cancer cells process zinc – a fact that could also help develop new cancer treatments, they suggest.
With these findings, they see a new understanding emerging about how different cancers affect different trace metals in the body. Such knowledge could lead to new diagnostic tools and treatments – a “two-pronged attack” on many cancers, says Dr. Larner, adding:
“Further research is already under way to see what changes in other metals may be caused by other cancers.”
This study is the latest in a line of research exploring new methods of detecting cancer earlier and more effectively. For instance, a team of scientists announced this summer that they are in the final stages of developing a simple blood test that will be able to predict a woman’s likelihood of developing breast cancer years before diagnosis by testing for a specific epigenetic signature — the way certain genes express themselves, or the way genes are turned “on” or “off” — that is present in women who had breast cancer and appears to serve as a diagnostic marker.