Sechenov University together with their German colleagues suggest a
new highly sensitive, quick, and pain-free method for diagnosing kidney
cancer. This method is based on measuring of the immune response to
arrestin-1, a retina protein that is synthesized in the cancerous cells
of kidneys.

Tumors can be benign or malignant. The first ones are not extremely
dangerous but they can evolve into the latter ones, and those, in turn,
are a cause of every sixth death in the world. Around 90-93% of all
kidney growths turn out to be malignant, and there are currently no
effective methods for early diagnostics. The initial stages of kidney
cancer have no signs or specific symptoms, and therefore patients often
get diagnosed with kidney cancer when it has already metastasized. At
this point, the doctors make prognosis not about the possibility of
recovery, but about a patient’s life expectancy.

Cancerous cells are the cells with considerable deviations in their
behavior, such as abnormal division, development, or protein synthesis.
Proteins may be synthesized in wrong quantities, in a wrong place, or
they may be of a poor quality. Normally arrestin-1 is synthesized in the
eye retina only, and its occurrence in another body organ may cause
intensive autoimmune response (i.e. a reaction against the body’s own
proteins). It’s already been discovered that arrestin-1 is present in
melanoma (malignant skin tumor). However, the idea to check the kidney
tumor cells for this type of protein and to measure the intensity of the
immune response to it turned out to be new for the scientific world.

The scientists wanted to find out whether it is possible to use the
antibodies to arrestin-1 as well as the protein itself as a marker of
cancerous kidney diseases. To do so, they dyed tissue sections, carried
out blood tests, and sequenced the samples. The samples for the
experiment were collected from patients that suffered from malignant and
benign kidney growths. The antibodies to arrestin-1 were found in the
blood serum of 75% of the patients; the protein itself was identified in
90% of benign tumors and in over 50% of cancerous ones. Increased
levels of arrestin-1 were also noticed in metastasis, especially in the
brain metastasis.

All subtypes of kidney tumors synthesize arrestin-1, which makes this
method inefficient for differential diagnostics. However, due to its
high sensitivity to benign growths, the method helps diagnose a disease
on early stages when the chances for recovery are at the highest. The
diagnostic procedure is reduced to simple blood test for the antibodies
to arrestin-1 instead of a biopsy that is technically complicated and
painful for a patient. “The discovery of arrestin-1 synthesis in cases of kidney cancer
suggests the possibility of developing anti-cancer vaccines on the
basis of this protein in the near future,” says Andrey Zamyatnin, a
co-author of the work, and the head of the Institute of Molecular
Medicine at Sechenov University.