MicroRNA as a Liquid Biomarker to Detect Malignancy in Small Testicular Masses

Area of Science:

• Urology
• Oncology
• Molecular Diagnostics

Background:

• Small testicular masses (STMs) are incidentally found in 1-4% of scrotal ultrasounds, with a low malignancy rate (13-21%).
• Accurate prediction of germ cell tumors (GCTs) in STMs is crucial for appropriate patient management.

Purpose of the Study:

• To investigate the potential of microRNAs (miRNAs) as non-invasive liquid biomarkers for GCT detection in STMs.
• To evaluate the diagnostic accuracy of specific miRNAs, particularly miR-371a-3p, for predicting testicular cancer.

Main Methods:

• Analysis of banked serum/plasma samples from 61 patients with STMs (37 GCTs, 20 benign histology) collected between 2009-2023.
• MiRNA expression profiling using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and digital droplet PCR for miR-371a-3p, miR-372, miR-373, and miR-367 across three international laboratories.
• Primary endpoint: diagnostic accuracy of miR-371a-3p for GCT prediction, measured by area under the curve (AUC).

Main Results:

• MiR-371a-3p demonstrated superior diagnostic performance compared to other evaluated miRNAs.
• Plasma extraction combined with RT-qPCR analysis (Vancouver lab) yielded the highest accuracy: 87% sensitivity, 91% specificity, and an AUC of 0.93.
• Other laboratories reported AUCs of 0.77 (Portugal) and 0.73 (Toronto), indicating variability in assay performance.

Conclusions:

• MiR-371a-3p is a sensitive and specific circulating biomarker for identifying GCTs within STMs.
• Plasma-based RT-qPCR is identified as the optimal method for miR-371a-3p analysis in this context.
• This study represents the largest series of STMs with banked blood samples, supporting the clinical utility of liquid biopsies for testicular cancer diagnostics.