Liquid-based kidney injury molecule-1 as a diagnostic and prognostic indicator in renal cell carcinoma: A systematic review and meta-analysis.

PURPOSE

Noninvasive biomarkers for renal cell carcinoma (RCC) are vital but scarce. Kidney injury molecule-1 (KIM-1) is a transmembranous glycoprotein that is sensitive and specific to kidney injury. KIM-1 is overexpressed in RCC, and its ectodomain can be detected in blood and urine. Here, we explored whether KIM-1 is a diagnostic or prognostic indicator in RCC.

METHODS

A comprehensive online literature search was performed in PubMed, Web of Science, Embase, Cochrane Library, ClinicalTrails, and Database of major urological or oncological congress. We screened the literature and extracted the data according to the selection criteria. The quality of eligible studies was measured via the Quality Assessment of Diagnostic Accuracy Studies-2 tool and the Newcastle-Ottawa scale. The certainty of the evidence (CoE) was assessed by the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) score. The sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), area under the curve of the summary receiver operating characteristic curve (AUROC), and survival outcomes were subsequently estimated in Stata and MetaDisc. Subgroup analysis, meta-regression, and sensitivity analysis were performed to reveal the source of heterogeneity.

RESULTS

A total of eight studies were included for further analysis. The pooled sensitivity of KIM-1 for RCC diagnosis was 0.78 (95% CI: 0.69-0.85, I = 84.61%, p < 0.01), and the pooled specificity was 0.79 (95% CI: 0.65-0.89, I = 90.72%, p < 0.01). The AUROC was 0.85 (95% CI: 0.82-0.88). A moderate CoE was indicated by GRADE score. A higher KIM-1 level was associated with worse disease-free survival (HR = 1.76, 95% CI: 1.48-2.09, I = 0.00%, p < 0.001). Study continent, number of study center, and sample type are the potential contributors of heterogeneity.

CONCLUSION

Liquid-based KIM-1 is a promising noninvasive biomarker for early RCC detection, surveillance, and prognosis prediction. More validations in large cohorts are needed to confirm these findings.