Tissue and urinary KIM-1 relate to tumor characteristics in patients with clear renal cell carcinoma

The objective of this prospective follow-up trial was to ascertain whether the urinary kidney injury molecule-1 (uKIM-1) associates with tumor tissue (tKIM-1) expression and with the pathological characteristics of clear renal cell carcinoma (cRCC) in radically nephrectomized (RN) and/or in partially nephrectomized (PN) patients with cRCC, pre- and postoperatively. This clinical study included 40 patients subjected to RN/PN (cRCC group) and 30 healthy volunteers (control group). Urinary KIM-1 was determined by ELISA TIM-1/KIM-1 kit and normalized by urinary creatinine. Immunohistochemical staining (monoclonal anti-human anti-TIM-1/KIM-1/HAVCR antibody) was used for semiquantitative analysis of the tKIM-1 expression and expressed as a score (% KIM-1 positively stained tubules). Both markers were interpreted in terms of the tumor characteristics comprising tumor size, Fuhrman grade, pathological (pT) stage, tumor/nodes/metastasis (TNM) stage, lymphovascular invasion and type of surgery RN/PN. Preoperative uKIM-1 was significantly higher in the cRCC group compared to controls, such as uKIM-1 was statistically higher in RN than in PN patients. Postoperatively, uKIM-1 decreased to control values. Expression of tKIM-1 was documented in all nephrectomized patients. Significant associations were achieved between uKIM-1 and tKIM-1 and with considered tumor characteristics, especially with tumor size and grade. Based on the accomplished associations, we found uKIM-1 as a highly sensitive marker for cRCC diagnosis. The clinical trial registration number: 1110-2012.