According to Tokar, there are currently two main options for doctors once they find a pancreatic cyst, and neither is ideal. One option is to advise the patient to have major surgery to remove the portion of the pancreas that contains the cyst, in hopes of eliminating the chance that it will develop into cancer. Unfortunately, with this approach, some patients will be subjected to the risks of surgery for a cyst that was never going to cause them any problems. The other option is to take a "watch-and-wait" approach, which can become costly, expose patients to additional radiation (i.e., if computerized tomography, or CT scans, are used), and may not always detect cancers within cysts at its earliest stages. "What we need are methods to identify benign cysts that do not have significant cancer risk, so that we can concentrate on the cysts that have the greatest risk of malignancy," Tokar says.
Using an endoscopic ultrasound-guided technique, Tokar and his colleagues collected fluid from the cysts of 20 research participants with a small needle. Yeung and his laboratory team then assayed the fluid to determine the number and type of proteins it contained. Identifying the proteins took more than eight months of continuous time with a mass spectrometer, an instrument that can determine the makeup of and thereby identify individual molecules. Among the proteins they found were members of three families of proteins previously proposed to be biomarkers for pancreatic cancer, called mucins, CEACAMs, and S100s.
"From these samples we've identified a panel of these proteins that could all be considered harbingers of cancer in some way," Yeung says. "Now that we know what we are looking for, we can use even more powerful spectrometry techniques to find this pattern of proteins fast enough that it could be used as part of a clinical service."
|Contact: Greg Lester|
Fox Chase Cancer Center