Serum Levels of MicroRNA371a-3p: A Highly Sensitive Tool for Diagnosing and Staging Testicular Germ Cell Tumours: A Clinical Case Series

Introduction: MicroRNA (miR)371a-3p was suggested to be a sensitive and specific new serum biomarker of germ cell tumours (GCTs); however, its clinical usefulness remains unproven. Patients, Methods: In 312 consecutive cases with various testicular diseases, serum levels of miR371a-3p were measured. Measurement results became available only after completion of treatment. Five patients with testicular seminoma were selected for review because of unanticipated clinical courses. Results: In each two patients, elevated miR levels heralded undetected primary testicular GCT and metastases despite inconclusive radiological findings. In one case, a normal miR371a-3p level correctly pointed to the absence of metastases contrary to clinical assessment. In all cases, knowledge about the miR371a-3p levels would have altered the clinical management. Conclusions: These cases highlight the exceptional usefulness of the new GCT biomarker. In contrast to classical markers, miR371a-3p can identify primary testicular GCT. The marker can aid in clinical decision making in cases with ambiguous clinical findings.