Kidney Injury Molecule-1 as a Biomarker for Renal Cancer: Current Insights and Future Perspectives-A Narrative Review.

Kidney injury molecule-1 (KIM-1) is a transmembrane protein that is significantly upregulated in renal cells following injury. It has considerable potential as a biomarker for diagnosing and monitoring renal cell carcinoma (RCC). This review examines KIM-1 expression across multiple biological sources-including tissue, blood, and urine-and highlights its strong association with RCC risk. Clinical studies have shown that KIM-1 levels decline within weeks after nephrectomy, underscoring its utility in assessing therapeutic response. Additionally, urinary KIM-1 levels correlate with histopathological outcomes following cisplatin treatment, supporting its role as a non-invasive marker for treatment effectiveness. Despite these promising findings, several challenges remain. These include variability in assay performance and the modulatory effects of the tumour microenvironment on KIM-1 expression. Overcoming these technical limitations is crucial for integrating KIM-1 into clinical workflows. Furthermore, its potential role in guiding combination therapies-such as tyrosine kinase inhibitors (TKIs), immune checkpoint inhibitors (ICIs), and mTOR inhibitors-could enhance therapeutic precision while minimizing toxicity. Continued research is essential to validate these applications and facilitate the routine clinical use of KIM-1 in RCC management.