Engineers from the University of California at San Diego (UCSD) and MIT devised a new strategy to detect cancer that has metastasized to the liver using probiotics, beneficial bacteria such as those found in yogurt. The results were published in Science Translational Medicine and might hold a potential impact for colon cancer detection.
Several types of cancer, such as colon and pancreatic, usually metastasize to the liver and treatment success is highly dependent on how soon they are detected. “There are interventions, like local surgery or local ablation, that physicians can perform if the spread of disease in the liver is confined, and because the liver can regenerate, these interventions are tolerated. New data are showing that those patients may have a higher survival rate, so there’s a particular need for detecting early metastasis in the liver,” said study author Sangeeta Bhatia, MIT.
Researchers used a harmless strain of E. coli that inhabits the liver and programmed it to produce a luminescent signal easily detected through a simple urine test. The team focused on the liver as it is the natural target for these bacteria and because it is a hard organ to image through conventional imaging techniques like CT scanning or magnetic resonance imaging (MRI); Moreover, it has been proved difficult to diagnose metastatic tumors in this particular organ.
The team used mice models of metastatic colon cancer (spread to the liver) and observed probiotic bacteria colonized almost 90 percent of all metastatic tumors without harmful side effects.
This could render it possible to detect liver tumors larger than 1 cubic millimeter, allowing patient monitoring after colon tumors’ removal as there are increased risks of liver recurrence.
Andrea Califano, a researcher not involved in the project from Columbia University, said that this work is “seminal and thought-provoking in terms of clearing a new path for investigating what can be done for early detection of cancer.”
“These bacteria could be engineered to cause genetic disruption of cancer cell function, deliver drugs, or reactivate the immune system,”added Califano.