An exosome-derived biomarker may be useful for the detection and diagnosis of early-stage pancreatic cancer, according to the findings of a recent study led by researchers from The University of Texas MD Anderson Cancer Center.
The biomarker, circulating cancer cell–derived exosomes (crExos) enriched in the protein glypican-1 (GPC1+), could serve as a noninvasive screening tool, the multinational team of researchers reported. “GPC1+ crExos were detected in small amounts of serum from about 250 patients with pancreatic cancer with absolute specificity and sensitivity, importantly distinguishing patients with early- and late-stage pancreatic cancer from those with chronic pancreatitis,” said Raghu Kalluri, M.D., Ph.D., a professor in and chair of MD Anderson’s Department of Cancer Biology and the study report’s senior author.
The researchers first established that GPC1, a membrane-anchored protein that is overexpressed in breast and prostate cancer cells, is a specific marker of cancer exosomes—virus-sized extracellular vesicles that are secreted by cancer cells and contain DNA, RNA, and proteins.
The team then isolated crExos from blood samples from 190 patients with pancreatic ductal adenocarcinoma (the most common form of pancreatic cancer) and 100 healthy donors and found that the levels of GPC1+ crExos in the cancer patients were significantly higher than those in the healthy donors, indicating a strong correlation between GPC1+ crExos and pancreatic cancer.
Further analysis revealed that the levels of GPC1+ crExos were consistently higher in patients with histologically validated pancreatic cancer precursor lesions than in healthy donors and patients with benign pancreatic disease and could be used to distinguish these groups. The researchers validated these findings in an independent cohort of 56 patients with pancreatic cancer, six patients with histologically confirmed benign pancreatic disease, and 20 healthy donors.
If detected in its early stages, pancreatic cancer can be cured with a pancreatoduodenectomy (Whipple procedure); however, because pancreatic cancer is often diagnosed at its later stages, only about 15% of patients qualify for such surgery.
“Studies comparing stage of disease with outcome following surgery suggest that death rates for pancreatic cancer would be reduced if the disease were diagnosed at an earlier stage,” Dr. Kalluri said. “Our findings present an unprecedented opportunity for informative early detection of pancreatic cancer.”
The study’s findings were reported in the June 24 issue of Nature.
OncoLog, August 2015, Volume 60, Issue 8