Esophageal cancer often isn't diagnosed until it is fairly advanced, and at that point, it is extremely difficult to treat. That's what makes recent findings by a team of Ohio researchers all the more encouraging. They've affirmed the viability of a new biomarker that could enable earlier diagnosis of the cancer, along with a noninvasive test that screens for it.
The researchers found that "aberrant" methylated vimentin appears to be a viable marker for Barrett's esophagus, a nonsymptomatic cellular change in the esophagus that is usually a precursor of esophageal cancer. Researchers from University Hospitals Case Medical Center's Seidman Cancer Center and Case Western Reserve University conducted the research, and they detailed what they found at the recent Digestive Disease Week conference in Chicago.
The team looked at esophageal specimens from healthy patients and those with Barrett's esophagus or esophageal cancer. They figured out that mutated methylated vimentin worked as a molecular marker to detect Barrett's esophagus. What's more, they found that using a nonendoscopic "brushing" technique of the esophagus was as effective as a biopsy (the traditional diagnostic standard) in detecting those biomarkers, and far less invasive. In previous research, they linked mutated vimentin methylation to patients at risk of esophageal cancer, finding it to be a common mutation in the neoplasia of the upper gastrointestinal tract.
Intervening when patients have earlier stage esophageal cancer, or the precursor Barrett's esophagus, would give doctors far more chances to successfully treat patients than they have now. Consider that esophageal cancer is often not detected until it is fairly advanced, and those patients can have a 5-year survival rate of less than 15%, the researchers said.
With that reality in mind, a number of groups have actively pursued the discovery and tested the viability of new esophageal cancer biomarkers.
Earlier this year, for example, a Johns Hopkins team concluded that cell-free circulating tumor DNA could serve as a noninvasive biomarker to help spot esophageal cancer, among other cancers. In January, researchers in Singapore and China determined that ADAR1 (an RNA-editing enzyme) multiplies in a common form of esophageal cancer. Last year, scientists at Imperial College London identified gastroesophageal cancer biomarkers in the gas given off by urine samples. Also in 2013, a group at the University of Texas MD Anderson Cancer Center identified microRNA expression signatures that they said could be used to monitor the advance of Barrett's esophagus into esophageal cancer. Others are pursuing similar efforts.
The University Hospitals/Case Western Reserve team hope their nonendoscopic "brushing" of the esophagus, combined with use of the methylated vimentin biomarker, could help make esophageal cancer screening both easier and cheaper. They also plan to pursue the discovery of other biomarkers that would allow similar earlier stage disease monitoring.
"Longer term, we hope to find additional markers that will allow the same approach to be used in the monitoring of Barrett's patients to detect early progression to more advanced disease," said Dr. Sanford Markowitz, a researcher on the project. He's an oncologist at UH Case Medical Center Seidman Cancer Center and teaches at Case Western Reserve School of Medicine.
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