Tumors form protein molecules that cause severe kidney disease
In numerous cancers, concomitant kidney diseases can be identified, the specific causes of which have remained unclear. Scientists at the University Medical Center Hamburg-Eppendorf (UKE) have now found that a special protein molecule that is formed in some tumors is obviously the cause of the development of kidney diseases.
According to the UKE scientists, they have succeeded in deciphering the connection between cancer and kidney disease. They identified a specific protein molecule that is apparently responsible for the development of severe kidney disease. The discovery could also have immediate practical benefits for patients, as increased protein excretion in the urine may indicate unrecognized cancer. The UKE researchers published their results in the “New England Journal of Medicine” and the “Journal of Clinical Investigation”.
Causes of kidney disease in cancer patients so far unclear
It has been known for more than 50 years that accompanying kidney diseases can develop with various types of cancer (especially colorectal cancer, lung and prostate cancer), the Hamburg scientists explain. However, “the reasons for the development of these kidney diseases have so far been unknown,” reports Professor Dr. Rolf Stahl from UKE. Now it has been possible to decipher the connections. The young scientists Dr. Elion Hoxha and Dr. Nicola Tomas from the group of Prof. Stahl in a patient with carcinoma of the gallbladder can prove that a special protein molecule (thrombospondin type 1 domain containing 7A) was formed in the tumor, reports the University Clinic Hamburg-Eppendorf.
Protein molecule Triggers a membrane-like glomerulonephritis
According to the researchers, the patient developed autoantibodies against the protein molecule, which subsequently led to kidney disease in the form of so-called membranous glomerulonephritis. The scientists had already described the protein molecule itself two years ago as the cause of the development of inflammatory kidney disease. Membrane glomerulonephritis can easily take a chronic course and often results in a nephrotic syndrome, which is associated with strong proteinuria (protein in the urine), water retention in the tissues (e.g. swollen or thick legs), certain metabolic disorders and possibly kidney pain. At worst, those affected experience life-threatening kidney failure.
With protein excretion in the urine for cancer screening?
In subsequent experiments, the UKE researchers were able to clearly demonstrate that antibodies to the protein molecule trigger membranous glomerulonephritis in tumor patients. According to the scientists, these findings could well have practical consequences for patients with increased protein excretion. Because "from our observations, conversely, for patients who increasingly excrete protein in the urine, it follows that they should be examined for the presence of these autoantibodies," reports Professor Stahl. In the case of a positive antibody detection, an intensive clarification should then be carried out, "whether there is a previously unrecognized cancer, which may then be recognized earlier and better treated." (Fp)