POKING a single cell with a nanoscale probe can reveal whether it is cancerous and can even help predict if the cancer is about to spread. The discovery could help doctors decide how aggressively they should treat a particular tumour.
The standard method for determining whether biopsied cells are cancerous is to examine their size and shape and to use antibody stains to detect the presence of proteins specific to certain cancers. However, neither technique reveals whether a tumour is about to spread, or 鈥渕etastasise鈥�.
In previous research on cultured cells, cancerous cells were found to be more compressible than normal cells, and that the squishier the cell is, the closer it is to metastasising (Biophysical Journal, ).
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Now James Gimzewski at the University of California, Los Angeles, and colleagues have found that cells taken directly from the body show the same properties, paving the way for a diagnostic test based on squishiness (Nature Nanotechnology, ).
Gimzewski and his team took fluid from the chest and abdominal cavities of patients with lung, breast and pancreatic cancer, which can contain both metastatic and healthy cells. They placed these cells under an atomic force microscope (AFM), which images objects at the nanoscale, and poked individual cells with a 400-nanometre-wide silicon tip. To gauge a cell鈥檚 softness, they measured how far its surface moved and how quickly it sprang back. These tests showed that metastatic cancer cells were 70 per cent softer than the healthy cells, despite being nearly identical in appearance. 鈥淚t鈥檚 like a bunch of tomatoes. You can鈥檛 determine their ripeness by looking at them, but by poking them you can figure it out,鈥� Gimzewski says.
鈥淚t鈥檚 like tomatoes. You can鈥檛 determine their ripeness just by looking at them鈥�
As well as detecting tumours that may be poised to metastasise, the technique could determine whether patients with fluid in their lungs or chest have cancer that is already spreading. 鈥淲e struggle with this on a daily basis,鈥� says Jianyu Rao of UCLA.
Gimzewski thinks the technique will also allow doctors to develop chemotherapy drugs based on the mechanical properties of particular cancer cells.
Cancer 鈥� Learn more about one of the world鈥檚 biggest killers in our comprehensive special report.
