In research that could one day make it possible to diagnose cancer without the need for a biopsy, researchers at the Johns Hopkins University School of Medicine have developed an MRI method that can detect a specific type of sugar molecule associated with cancerous cells.
While other imaging tests, including CT scans and mammograms, can be used to detect tumors, the Johns Hopkins researchers point out that a biopsy is typically required to directly study cells and determine whether a growth is malignant or benign. However, their new MRI technique may make those biopsies more effective, or even replace them completely.
The method, which is described in a paper currently available online Friday in the journal Nature Communications, noninvasively detects sugar molecules that are shed by the outer membranes of cancerous cells. Thus far, the technique has only been tested in mice and in cells grown in a test tube, but the authors believe that it shows promise as a non-invasive diagnostic tool.
Imaging cellular slime
“We think this is the first time scientists have found a use in imaging cellular slime,” explained Dr. Jeff Bulte, a radiology and radiological science professor at the Johns Hopkins Institute for Cell Engineering. “As cells become cancerous, some proteins on their outer membranes shed sugar molecules and become less slimy, perhaps because they’re crowded closer together.”
He added that if he and his colleagues are able to program the MRI to detect sugars attached to a specific protein, they might be able to tell the difference between regular cells and cancerous ones. Their work builds on recent research indicating that fine-tuned imaging techniques are able to detect glucose without using dyes based on how it interacts with surrounding water molecules.
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Other scientists have used MRI to image proteins on the outside of cells that had lost their sugar, but those techniques require injectable dyes. Dr. Bulte’s team, however, compared MRI readings from a type of protein known as mucins both with and without sugars attached to find out what changes happened to the signal.
They then looked for that altered signal in four types of lab-grown cancer, and found drastically reduced levels of mucin-attached sugars when compared to normal cells. Lead author Dr. Xiaolei Song said that this was the first time that a property integral to cancer cells was used instead of an injected dye to detect cancer cells.
Advantages of this method
“The advantage of detecting a molecule already inside the body is that we can potentially image the entire tumor,” she explained in a statement. “This often isn’t possible with injected dyes because they only reach part of the tumor. Plus, the dyes are expensive.”
While Bulte cautions that more testing is required to prove that the technique could be used to help diagnose cancer in humans, it does show promise. He and his colleagues now plan to see if they can distinguish more types of cancerous tumors from benign masses in live mice using the MRI technique.
Provided additional testing is successful, Bulte and Song believe that the method could be used to detect cancer at an early stage, as well as to monitor response to chemotherapy and to guide biopsies to ensure sampling of the most malignant part of a tumor. Eventually, they hope that the MRI technique could make at least some biopsies unnecessary.