Proteins in urine indicate kidney cancer

The presence of a pair of proteins in urine could lead to an earlier and more accurate diagnosis of kidney cancer according to researchers at Washington University School of Medicine in St Louis.

There is currently no diagnostic test for kidney cancer, but Evan D Kharasch and Jeremiah J Morrissey hope that their discovery may lead to routine screening for the disease in a doctor’s surgery, using a non-invasive urine test.

“We believe that in the same way we use mammograms to screen for breast cancer and blood tests to screen for prostate cancer, we may have the opportunity to detect these proteins in urine as a way to screen for kidney cancer,” Kharasch said.

The duo studied urine samples from 76 individuals – 42 with kidney cancer, 15 who had no cancer but were to undergo abdominal surgery and 19 healthy patients – and found elevated levels of   aquaporin-1 (AQP1) and adipophilin (ADFP) in the urine samples from kidney cancer patients. The levels were normal in the other candidates.

“When patients come to surgery, it tends to be late in the process and many have already progressed to the stage where the prognosis is pretty bleak,” said Morrissey, “Screening patients to find kidney cancer when it is still small and treatable could save a number of lives and preserve kidney function in many people.” He said it may also be the difference between losing the whole kidney, or extracting the tumour from the healthy portions of the kidney.

Kharasch and Morrissey say that more research is needed to see how early on in the disease process levels of AQP1 and ADFP rise, and whether their concentrations might correspond to the size of a kidney tumour. Further testing is needed to determine whether people with other types of kidney disease also have high levels of the proteins in their urine.