Promising retrospective results raise long-term possibilities for labs, even as clinical and regulatory plans remain unclear.
NIH-supported researchers have identified a new four-marker blood test that may improve the early detection of pancreatic ductal adenocarcinoma (PDAC), one of the deadliest and most difficult cancers to diagnose at a treatable stage. The findings, published in Clinical Cancer Research, could have long-term implications for clinical laboratories if the approach is validated in future studies, though significant hurdles remain before it could reach routine clinical use.
Pancreatic cancer has a notoriously poor prognosis, largely because it is often diagnosed after the disease has already advanced. According to the researchers, “only about 1 in 10 pancreatic cancer patients survive more than five years from diagnosis.” By contrast, survival improves substantially when tumors are detected early. However, as the authors note, “there are no current screening methods” capable of reliably identifying pancreatic cancer before symptoms appear.
Why Existing Markers Fall Short
In the study, investigators from the University of Pennsylvania’s Perelman School of Medicine and the Mayo Clinic used a phased, retrospective approach to evaluate blood-based biomarkers using banked samples. Two previously studied markers—carbohydrate antigen 19-9 (CA19-9) and thrombospondin 2 (THBS2)—were included because of their historical relevance in pancreatic cancer research. CA19-9, for example, is commonly used in clinical settings to monitor treatment response.
However, neither marker has proven suitable for population screening. CA19-9 “can be elevated in people with benign conditions such as pancreatitis and bile duct obstruction,” and some individuals “don’t produce it at all due to genetic factors,” limiting its clinical specificity and sensitivity. These limitations are well known to laboratory professionals who routinely interpret CA19-9 results in oncology workflows.
The researchers identified two additional proteins—aminopeptidase N (ANPEP) and polymeric immunoglobulin receptor (PIGR)—that were elevated in early-stage pancreatic cancer patients compared with healthy controls. When combined with CA19-9 and THBS2, the resulting four-marker panel demonstrated improved performance.
For all cancer stages combined, the panel distinguished pancreatic cancer cases from non-cases 91.9% of the time at a false positive rate of 5%. For early-stage disease (stage I and II), the test identified 87.5% of cases.
“By adding ANPEP and PIGR to the existing markers, we’ve significantly improved our ability to detect this cancer when it’s most treatable,” said lead investigator Kenneth Zaret, PhD. (Photo credit: Perelman School of Medicine at the University of Pennsylvania)
Encouraging Performance, Early Days
Importantly for clinical laboratories, the test was able to differentiate cancer patients not only from healthy individuals, but also from patients with non-malignant pancreatic conditions, including pancreatitis—an area where many candidate biomarkers have historically struggled.
Despite the promising results, the authors stress that the findings are preliminary. “Our retrospective study findings warrant further testing in larger populations, particularly in people before they show symptoms,” Zaret said. He added that so-called “prediagnostic” studies would be required to determine whether the assay could be used as a screening tool in high-risk populations, such as individuals with a family history of pancreatic cancer or known genetic risk factors.
Notably, neither the NIH announcement nor the published coverage includes any public information about plans for FDA submission, commercialization, or clinical deployment of the test. There is no mention of whether the assay would be developed as a laboratory developed test (LDT), licensed to a diagnostics company, or pursued through a formal regulatory pathway.
For now, the four-marker panel represents a research advance rather than a near-term clinical offering. Still, it highlights how multi-analyte blood tests may eventually reshape cancer screening—and presents an area for clinical laboratories to watch closely as validation studies progress.
—Janette Wider
