School of Medicine researchers have developed a noninvasive method to screen for kidney cancer that involves measuring the presence of proteins in the urine. The findings are reported March 19 in the journal JAMA Oncology.
The researchers found that the protein biomarkers were more than 95 percent accurate in identifying early-stage kidney cancers. In addition, there were no false positives caused by non-cancerous kidney disease.
“These biomarkers are very sensitive and specific to kidney cancer,” said senior author Evan D. Kharasch, MD, PhD.
Like most cancers, kidney tumors are easier to treat when diagnosed early. But symptoms of the disease, such as blood in the urine and abdominal pain, often don’t develop until later, making early diagnosis difficult.
“The most common way that we find kidney cancer is as an incidental, fortuitous finding when someone has a CT or MRI scan,” said Kharasch, the Russell D. and Mary B. Shelden Professor of Anesthesiology. “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.”
With researchers from the Alvin J. Siteman Cancer Center, the Mallinckrodt Institute of Radiology and the Division of Urologic Surgery, Kharasch and principal investigator Jeremiah J. Morrissey, PhD, professor of anesthesiology, analyzed urine samples from 720 patients at Barnes-Jewish Hospital who were about to undergo abdominal CT scans for reasons unrelated to suspicion of kidney cancer.
Results of the scans let the investigators determine whether patients might have kidney cancer. As a comparison, they also analyzed samples from 80 healthy people and 19 patients previously diagnosed with kidney cancer.
The researchers measured levels of two proteins in the urine — aquaporin-1 (AQP1) and perlipin-2 (PLIN2). None of the healthy people had elevated levels of either protein, but patients with kidney cancer had elevated levels of both proteins.
About 15 percent of kidney masses found by CT scans are not malignant. The only way to know definitively is to operate. Kharasch and Morrissey are using the findings to develop an easy-to-use, more widely available screening test.