PURPOSE Previous studies suggested that serum levels of microRNA (miR)-371a-3p (so-called M371 test) have a much higher sensitivity and specificity than the classic markers of testicular germ cell tumors (GCTs) and are applicable toward both seminoma and nonseminoma. We sought to confirm the usefulness of this test as a novel biomarker for GCT. PATIENTS AND METHODS In a prospective, multicentric study, serum samples of 616 patients with testicular GCTs and 258 male controls were examined for serum levels of miRNA-371a-3p (miR levels) by quantitative polymerase chain reaction. The GCT population encompassed 359 patients with seminoma and 257 with nonseminoma; 371 had clinical stage I disease, 201 had systemic disease, and 46 had relapses. Paired measurements before and after orchiectomy were performed in 424 patients; 118 with systemic disease had serial measurements during treatment. miR levels were compared with those of β-human chorionic gonadotropin, α-fetoprotein, and lactate dehydrogenase. RESULTS For the primary diagnosis of GCT, the M371 test showed a sensitivity of 90.1%, a specificity of 94.0%, an area under the curve of 0.966 upon receiver operating characteristic analysis, and a positive predictive value of 97.2%. α-Fetoprotein, β-human chorionic gonadotropin, and lactate dehydrogenase had sensitivities of less than 50% in seminoma and slightly higher sensitivities in nonseminomas. miR levels were significantly associated with clinical stage, primary tumor size, and response to treatment. Relapses had elevated miR levels that subsequently dropped to normal upon remission. Teratoma did not express miR-371a-3p. CONCLUSION The M371 test outperforms the classic markers of GCT with both a sensitivity and a specificity greater than 90%. All histologic subgroups, except teratoma, express this marker. The test could be considered for clinical implementation after further validation.

The miRNA miR-371a-3p is a specific and sensitive novel serum GCT biomarker that accurately correlates with disease activity. Validation of this test in a large-scale prospective study is needed. PATIENT SUMMARY: miR-371a-3p is a novel serum marker for germ cell tumours that is expressed by 88.7% of patients and thus is far more sensitive and specific than classical serum markers. It correlates with tumour burden and treatment results. Validation in a large patient cohort is needed.

In our series the poppy seed test had the highest sensitivity to detect colovesical fistulas. However, abdominopelvic computerized tomography, colonoscopy and cystoscopy are essential diagnostic procedures because the presence of colon or bladder cancer as an underlying cause of colovesical fistula will determine further therapy.

Negative prognostic features increase with tumor diameter and they are associated with even small tumors. However, above a tumor size of 3.0 cm there is a sharp increase in the incidence of negative prognostic parameters. New diagnostic tests are warranted to better stratify patients with respect to treatment aggressiveness for small incidental renal tumors.