Cause of kidney disease identified in cancer patients

Tumors form protein molecules that cause severe kidney disease
Concomitant kidney diseases have been identified in numerous cancers, the concrete causes of which have remained unclear. Scientists at the University Medical Center Hamburg-Eppendorf (UKE) have now discovered that a specific protein molecule, which is formed in some tumors, is obviously the cause of the development of kidney disease.

According to the UKE scientists, they have managed to decipher the link between cancer and kidney disease. They identified a specific protein molecule, which is apparently responsible for the development of severe kidney disease. The discovery could also have immediate practical benefits for patients, as increased urinary protein excretion may be indicative of undetected cancers. Their findings have been published by UKE researchers in the New England Journal of Medicine and the Journal of Clinical Investigation.

Many cancer patients develop concomitant severe kidney disease in the form of membranous glomerulonephritis. The cause is certain protein molecules that are formed by tumors. (Image: designua / fotolia.com)

Causes of kidney disease in cancer patients so far unclear
It has been known for more than 50 years that accompanying kidney diseases can arise in various cancers (especially colon cancer, lung and prostate cancer), explain the Hamburg scientists. However, "the reasons for the development of these kidney diseases have so far been obscure", reports Professor Dr. med. Rolf Stahl from the UKE. Now it was possible to decode the connections. That's how the junior scientists Dr. Ing. Elion Hoxha and dr. Nicola Tomas from the group of Prof. Stahl in a patient with a carcinoma of the gallbladder prove that in the tumor a special protein molecule (Thrombospondin Type 1 Domain Containing 7A) was increasingly formed, reports the University Hospital Hamburg-Eppendorf.

Protein molecule triggers a membranous glomerulonephritis
According to the researchers, the patient developed autoantibodies against the said protein molecule, which subsequently caused kidney disease in the form of so-called membranous glomerulonephritis. According to the UKE, two years ago, the scientists themselves characterized the protein molecule as the cause of the development of inflammatory kidney disease. Membranous glomerulonephritis can easily become chronic and often results in a nephrotic syndrome associated with severe proteinuria (protein in the urine), water retention in the tissues (e.g., swollen or fat legs), certain metabolic disorders, and possibly kidney pain. In the worst case, sufferers suffer a life-threatening kidney failure.

With protein excretion in urine for cancer screening?
In subsequent experiments, researchers from UKE clearly demonstrated that antibodies to the protein molecule trigger membranous glomerulonephritis in tumor patients. In the opinion of the scientists, these findings could have very practical consequences for patients with increased protein excretion. Because "from our observations results in reverse for patients who excrete more protein in the urine, that they should be examined for the presence of these autoantibodies," says Professor Stahl. In the case of a positive antibody detection then an intensive clarification should be made "if there is a previously unrecognized cancer, which may then be detected sooner and be better treated." (Fp)