MicroRNA-371a-3p—The Novel Serum Biomarker in Testicular Germ Cell Tumors

SIMPLE SUMMARY: This review describes that miR371 is much more sensitive and specific than the classical serum biomarkers of testicular germ cell cancer. There is a huge potential for miR371 for initial diagnosis, monitoring treatment, and follow-up. However, miR371 is not expressed in teratoma. Currently, studies are underway to determine the importance of miR371 in the early detection of recurrences of testicular tumors under surveillance. Further studies will examine the role of miR371 in residual tumors after chemotherapy, with the aim of uncovering viable tumor components. ABSTRACT: Introduction: Testicular germ cell tumors (TGCTs) are a paradigm for the use of serum tumor markers in clinical management. However, conventional markers such as alpha-fetoprotein (AFP), beta-human chorionic gonadotropin (hCG), and lactate dehydrogenase (LDH) have quite limited sensitivities and specificities. Within the last decade, the microRNA-371a-3p (miR371) emerged as a possible new biomarker with promising features. Areas covered: This review covers the typical features as well as possible clinical applications of miR371 in TGCT patients, such as initial diagnosis, therapy monitoring, and follow-up. Additionally, technical issues are discussed. Expert opinion: With a sensitivity of around 90% and specificity >90%, miR371 clearly outperforms the classical serum tumor markers in TGCTs. The unique features of the test involve the potential of modifying recent standards of care in TGCT. In particular, miR371 is expected to aid clinical decision-making in scenarios such as discriminating small testicular TGCT masses from benign ones prior to surgery, assessing equivocal lymphadenopathies, and monitoring chemotherapy results. Likewise, it is expected to make follow-up easier by reducing the intensity of examinations and by sparing imaging procedures. Overall, the data presently available are promising, but further prospective studies are required before the test can be implemented in standard clinical care.