[Aberrant expression of arrestin-1 and recoverin in kidney tumors].

Introduction: Early diagnosis of renal cell carcinoma (RCC) is extremely difficult, due to the late development of clinical manifestations. The study of the aberrant expression of tumor-associated antigens and a production of autoantibodies to these proteins seems promising and novel method for RCC diagnosis.

Aim: To evaluate the possibility of using arrestin-1 (Arr-1), recoverin (Rec) and autoantibodies against arrestin-1 (AAA1) and recoverin (AAR) as a kidney tumor biomarker.

Materials And Methods: Primary kidney tumors and metastases of 62 patients were investigated. For immunohistochemical studies, tissues were incubated with polyclonal antibodies against Rec and Arr1 as the main antibodies. Detection of AAR and AAA-1 in the serum of patients was performed using Western Blot analysis according to a standard protocol.

Results: Among 62 tumors, renal cell carcinoma (RCC) constitutes 50 cases (86.4%), and oncocytoma was diagnosed in 12 patients (19.4%). In 11 (22%) cases of RCC, distant metastases were detected. Positive expression of Rec was observed in almost 71% of all types of kidney tumors. In 61.3% of patients with RCC, Arr-1 expression was seen. In the serum, AAR was found only in 1 patient (1.6%) with RCC. However, unlike AAR, AAA-1 in the serum of patients was observed much more often (75.8%).

Conclusion: According to our data, the presence of AAA1 in the serum, unlike AAR, can be considered as an early kidney tumor biomarker. The high expression of recoverin and arrestin-1 in kidney tumors suggests the use of these proteins in future as a marker for the diagnosis or even as a potential target for immunotherapy.