By Stephanie Murg, Managing Director, G2 Intelligence
A noninvasive screening method may hold the promise of improved outcomes for patients with kidney cancer, which affects approximately 65,000 people each year in the United States. The key is early diagnosis: If kidney cancer can be detected before it spreads, 80 percent of patients survive. An encouraging study of the new urine-based test, developed by researchers at the Washington University School of Medicine in St. Louis, was published online on March 19 in JAMA Oncology.
“The most common way that we find kidney cancer is as an incidental, fortuitous finding when someone has a CT or MRI scan,” says Evan D. Kharasch, M.D., Ph.D., senior author of the study and a professor of anesthesiology at Wash U. “It’s not affordable to use such scans as a screening method, so our goal has been to develop a urine test to identify kidney cancer early.”
Kharasch, principal investigator Jeremiah J. Morrissey, Ph.D., and colleagues used enzyme-linked immunosorbent assays and Western blots to evaluate the clinical utility, sensitivity, and specificity of purine aquaporin-1 (AQP1) and perilipin-2 (PLIN2) as unique, noninvasive biomarkers for malignant clear cell or papillary renal cell carcinoma (RCC). They found that these proteins were more than 95 percent accurate in identifying early-stage kidney cancers.
“Each protein, or biomarker, individually pointed to patients who were likely to have kidney cancer, but the two together were more sensitive and specific than either by itself,” says Morrissey. “When we put the two biomarkers together, we correctly identified the patients with kidney cancer and did not have any false positives.”
The researchers are now working to develop an easy-to-use screening test for kidney cancer. Kharasch and Morrissey envision a screening test akin to a mammogram or colonoscopy that would be designed to identify cancer at an early, pre-symptomatic stage at which treatment can be most effective.