Urinary miRNA Analysis for Clear Cell Renal Cell Carcinoma: miR-20a as a Key Endogenous Normalizer

Area of Science:

• Biomarkers and diagnostics
• Molecular biology
• Urology

Background:

• Urinary microRNAs (miRNAs) show potential as noninvasive biomarkers for cancer detection.
• Inconsistent normalization strategies hinder the clinical utility and reproducibility of urinary miRNA profiling.
• Standardizing pre-analytical conditions is crucial for reliable miRNA analysis.

Purpose of the Study:

• To evaluate the stability of miR-20a as an endogenous normalizer for urinary miRNA profiling in clear cell renal cell carcinoma (ccRCC).
• To assess the impact of a urine stabilizing solution on pre-analytical standardization.
• To establish a reproducible workflow for urinary liquid biopsy in ccRCC detection.

Main Methods:

• Analysis of 99 urine samples (healthy, pre-surgery ccRCC, post-operative ccRCC).
• Quantification of six candidate urinary miRNAs (miR-20a, miR-15b, miR-16, miR-15a, miR-210-3p, miR-let-7b) using RT-qPCR.
• Stability assessment of candidate miRNAs using RefFinder, integrating geNorm, normFinder, BestKeeper, and ΔCt methods.

Main Results:

• miR-20a was identified as the most stable endogenous normalizer among the six candidates.
• Raw Ct values of miR-20a exhibited normal distribution and minimal variability across patient groups and storage durations.
• miR-20a stability was unaffected by tumor staging, grading, or urine storage time.

Conclusions:

• miR-20a is a robust and reliable endogenous normalizer for urinary miRNA analysis in ccRCC.
• Standardized pre-analytical phase using a urine stabilizing solution enhances reproducibility.
• Development of reproducible urinary liquid biopsy workflows for ccRCC is feasible, even with delayed sample processing.