Researchers from Germany have developed a device that detects cancer cells by measuring their elasticity. The extremely sensitive device, the size of a shoebox, uses a laser to take its measurements.
Researchers from Germany have developed a device that detects cancer cells by measuring their elasticity. The extremely sensitive device, the size of a shoebox, uses a laser to take its measurements.
Traditional methods of cancer testing require 10,000 – 100,000 abnormal cells to diagnose cancer. But the new method can provide an answer with the help of a small amount of 50 tumor cells, and then it will be possible to take biopsies containing a small number of cells from the patients' bodies.
So far, the new technology has been tested in diluted cell mixtures in the laboratory, but its creators hope to see its final use in hospitals. "We really have a medical application in principle," says Joseph Kass (K�s) of the University of Leipzig, Germany, who helped build the device.
The laser test relies on the fact that healthy cells contain an internal "scaffolding system" or "cytoskeleton" that helps keep the cell's contents in place. When cells become cancerous, the cytoskeleton retracts and as a result the cells become more elastic.
When a laser beam from the device enters the cell, the light gains momentum due to the different conditions inside the cell. According to the law of conservation of momentum, the cell must lose an equal but opposite amount, so that its membrane tilts towards the light source. "The cell kicks back," Cass explains. When the laser light leaves the cell, it loses momentum and pulls the opposite side of the cell with it. By prolonged irradiation of a laser, the cell is stretched to its limit.
Without a strong skeleton, cancer cells are 40% easier to expand than their healthy counterparts. And cells from metastatic tumors – those that have spread through the body – are 30% more stretchable than early-stage cancer cells. This means that the laser can potentially gauge how far the disease has progressed. "The softest cells are the most aggressive," Kass says.
These days, doctors cannot diagnose metastases without finding out the location of secondary tumors. The new laser method will destroy metastatic cells based on cell flexibility alone, he says. In breast cancer, for example, the researchers believe that this will be reflected in fewer unnecessary mastectomies due to guessing as to the rate of spread of the disease.
The test should be much more sensitive than cancer tests that use molecular markers to mark abnormal cells. Kass explains that when cancer-causing genes start working in a cell, they cause a small change in the proteins that make it up and this has an exponential effect on flexibility. The hidden changes in the cell's DNA, which current cancer detection methods focus on, are nowhere near as dramatic as the cell's flexibility
As its creators claim, when the laser examines a sample containing at least fifty tumor cells, it can detect cancer in more than 90% of cases. Nevertheless, more studies are needed to decide whether it can detect all types of cancer. "This will require years of research," says Kass, who presented the findings at a meeting of the Institute of Physics in Warwick, UK, this week.
To say that such a machine can replace a microscope for cancer screening would be "somewhat hasty", says Peter Sasieni, spokesman for the London-based Cancer Research Organization. He adds, however, that the innovative device could help in future medical applications.
