This is one in a series presenting news on technology and innovation, made possible with generous support from the Lemelson Foundation.
A cancerous lump in the breast can be dangerous, but it seldom kills. However, if cancer cells leave that lump, the satellite tumors that form in other organs pose a much bigger threat. And those tiny new cancers can be hard to spot. Now, a study shows that implanting a small device beneath the skin might help save lives by catching cancerous cells after they begin wandering — but before they settle down to form new tumors.
The implant has not yet been tested in people. But when placed into mice with tumors, the device trapped runaway cancer cells. These cells are known as metastatic (MET-uh-STAT-ik) cells. They signal worsening disease. And the mice lived longer when researchers cut away the tissue around the implant, where those metastatic cells had been lurking.
A team at the University of Michigan in Ann Arbor reported these findings September 15 in Cancer Research.
The invention has “a lot of potential,” says breast surgeon Charusheela Andaz. “It’s a novel idea.” Andaz, who did not help with the study, works at Maimonides Medical Center in New York City. The new implant could be useful in people at risk of breast cancer — or in patients who have been treated successfully but whose cancer could return, she suspects.
Surgeon Jacqueline Jeruss is one of the new study’s authors. She gets sad and frustrated when a patient's breast cancer spreads to the lung, liver, bone or brain. For years her husband, Lonnie Shea, listened to her talk about how bad she felt for such patients.
Shea also works at the University of Michigan. As a chemical engineer, he uses chemistry to create useful products. He and Jeruss thought about patients whose cancer had been cured but could return. It’s as though those patients have a “ticking time bomb,” Shea says. “The cancer could come back, but they don’t know when.”
That idea inspired the couple to develop the new cancer-catching implant.
As the duo brainstormed, a long-held theory came to mind. Some researchers believe that as cancers begin growing in the breast, they tend to stay put. “They haven’t found a way to grow up and leave home yet,” says Jeruss. “They haven’t yet received the education to fly out of the nest.”
Eventually, some young cancer cells may start to roam. They don’t just wander randomly, however. They tend to go where conditions are best for resettling. Scientists don’t know everything about what makes the new sites attractive to migrating cancer cells. But they know that such sites contain immune cells — part of the body’s defense against infections and foreign invaders. Those immune cells in turn lure cancer cells that are on the move.
Jeruss and Shea’s new device is about the size of a pencil eraser. It’s made of the same material as the stitches that doctors use to sew up wounds. Since immune cells are programmed to recognize foreign material, they flock to the implant. There they act “like a decoy,” Jeruss says. They build up around the implant and lure metastatic cells.
Last year Shea and Jeruss did mouse experiments to show the implant could attract metastatic cells. The new study took things further by showing cancer-bearing mice with the implants live longer.
In the new tests, half of the mice received implants. One month later, all of the animals received an injection of breast cancer cells. Ten days after that, the researchers did surgery to cut out the animals’ tumors. Another five days after that, they checked each mouse’s liver and brain. Breast cancer cells often migrate to these organs. But in the mice with implants, 64 percent fewer cancer cells spread to the liver, and 75 percent fewer made it to the brain. Four in every 10 of the animals with implants were still alive six months later. In contrast, all of the mice without implants died within 40 days of the removal of their tumors.
Another pleasant surprise: Cells trapped by the implant did not form new tumors.
The researchers hope to test their device in people soon to see if the implant is safe and attracts cancer cells as it did in mice. The team also could retrieve cells from participants’ implants. Back at the lab, the researchers could study those metastatic cells to figure out what’s special about them, Jeruss says. For example, they could look for unique genes and proteins that are in these cells but not in cancer cells that do not metastasize. Those insights might help the team develop new cancer-fighting therapies that are tailored to tackle the most troublesome cells.
cancer Any of more than 100 different diseases, each characterized by the rapid, uncontrolled growth of abnormal cells. The development and growth of cancers, also known as malignancies, can lead to tumors, pain and death.
cell The smallest structural and functional unit of an organism. Typically too small to see with the naked eye, it consists of watery fluid surrounded by a membrane or wall. Animals are made of anywhere from thousands to trillions of cells, depending on their size. Some organisms, such as yeasts, molds, bacteria and some algae, are composed of only one cell.
chemical engineer A researcher who uses chemistry to solve problems related to the production of food, fuel, medicines and many other products.
chemistry The field of science that deals with the composition, structure and properties of substances and how they interact with one another. Chemists use this knowledge to study unfamiliar substances, to reproduce large quantities of useful substances or to design and create new and useful substances.
defense (in biology) A natural protective action taken or chemical response that
gene (adj. genetic) A segment of DNA that codes, or holds instructions, for producing a protein. Offspring inherit genes from their parents. Genes influence how an organism looks and behaves.
immune Able to ward off a particular infection. Alternatively, this term can mean to show no impacts from a particular poison or process. More generally, the term may signal that something cannot be hurt by a particular drug, disease or chemical.
implant A device manufactured to replace a missing biological structure, to support a damaged biological structure, or to enhance an existing biological structure. Examples include artificial hips, knees and teeth; pacemakers; and the insulin pumps used to treat diabetes.
infection A disease that can spread from one organism to another. It’s usually caused by some sort of germ.
insight The ability to gain an accurate and deep understanding of a situation just by thinking about it, instead of working out a solution through experimentation.
liver An organ of the body of animals with backbones that performs a number of important functions. It can store fat and sugar as energy, breakdown harmful substances for excretion by the body, and secrete bile, a greenish fluid released into the gut, where it helps digest fats and neutralize acids.
metastatic An adjective that describes one or more cancer cells that have been shed by from some distant organ or body part. They can now create a satellite cancer at some new site.
migrate To move long distances (often across many countries) in search of a new home. (in biology) To travel from one place to another at regular times of the year to find food or more hospitable conditions (such as better weather). Species that migrate each year are referred to as being migratory.
organ (in biology) Various parts of an organism that perform one or more particular functions. For instance, an ovary is an organ that makes eggs, the brain is an organ that interprets nerve signals and a plant’s roots are organs that take in nutrients and moisture.
proteins Compounds made from one or more long chains of amino acids. Proteins are an essential part of all living organisms. They form the basis of living cells, muscle and tissues; they also do the work inside of cells. The hemoglobin in blood and the antibodies that attempt to fight infections are among the better-known, stand-alone proteins. Medicines frequently work by latching onto proteins.
risk The chance or mathematical likelihood that some bad thing might happen. For instance, exposure to radiation poses a risk of cancer. Or the hazard — or peril — itself. Among cancer risks that the people faced were radiation and drinking water tainted with arsenic.
satellite A moon orbiting a planet or a vehicle or other manufactured object that orbits some celestial body in space. (in cancer biology) A cancer cell or group of cells that leave a tumor, travel through the body, and set up a little cancer at a new site.
spawn To release or fertilize eggs in an aquatic environment.
theory (in science) A description of some aspect of the natural world based on extensive observations, tests and reason. A theory can also be a way of organizing a broad body of knowledge that applies in a broad range of circumstances to explain what will happen. Unlike the common definition of theory, a theory in science is not just a hunch. Ideas or conclusions that are based on a theory — and not yet on firm data or observations — are referred to as theoretical. Scientists who use mathematics and/or existing data to project what might happen in new situations are known as theorists.
tissue Any of the distinct types of material, comprised of cells, which make up animals, plants or fungi. Cells within a tissue work as a unit to perform a particular function in living organisms. Different organs of the human body, for instance, often are made from many different types of tissues. And brain tissue will be very different from bone or heart tissue.
tumor A mass of cells characterized by atypical and often uncontrolled growth. Benign tumors will not spread; they just grow and cause problems if they press against or tighten around healthy tissue. Malignant tumors will ultimately shed cells that can seed the body with new tumors. Malignant tumors are also known as cancers.
unique Something that is unlike anything else; the only one of its kind.
Journal: S.S. Rao et al. Enhanced survival with implantable scaffolds that capture metastatic breast cancer cells in vivo. Cancer Research. Vol. 76, September 15, 2016, p. 5209. doi: 10.1158/0008-5472.CAN-15-2106.
Journal: S.M. Azarin et al. In vivo capture and label-free detection of early metastatic cells. Nature Communications. Vol. 6, September 8, 2015. doi:10.1038/ncomms9094.