Targeted serum miRNA (TSmiR) test for diagnosis and follow‐up of (testicular) germ cell cancer patients: A proof of principle

Abstract

Germ cell cancers (GCC) are the most frequent malignancy in young Caucasian males. GCC can consist of seminomas (SE) and non-seminomas (malignant NS: embryonal carcinoma (EC), yolk sac tumor (YS), choriocarcinoma (CH) and teratoma (TE)). Current serum-markers used for diagnosis and follow-up (AFP, hCG) are predominantly related to YS and CH and marker positivity can vary during disease. Therefore, stable markers consistently identifying more GCC components, specifically the stem cell components SE and EC, are of interest. Expression of the embryonic stem cell miR-371-3 and miR-302/367 clusters in SE/EC/YS suggest possible application of these micro-RNAs as GCC tumor-markers. The TSmiR protocol constitutes a complete, quality-controlled pipeline for the detection of miRs in serum, based on magnetic bead-based purification and qPCR quantification. As a proof of principle, TSmiR was applied to five independent serum sample series including 80 GCCs, 47 controls, 11 matched pre/post orchidectomy samples and 12 no-GCC testicular masses. GCC serum samples showed a consistent, significant (p < 0.0064) increase of miR-371/372/373/367 levels. Analogous, serum levels returned to baseline after orchidectomy (stage-I disease). Moreover, there was a trend toward higher miR levels in patients with metastasis. These results imply suitability for diagnosis and follow-up. TSmiR showed an overall sensitivity of 98%, clearly outperforming the traditional serum markers AFP/hCG (36%/57%, sensitivity(AFP) = 3%/45%; sensitivity(hCG) = 62%/66%, SE/NS). TSmiR misclassified one tumor as a control. Serum AFP/hCG and TSmiR combined identified all T samples correctly. In conclusion, TSmiR constitutes a highly sensitive and reproducible serum test for GCC patients, suitable to be prospectively tested for diagnostic and follow-up purposes.

MicroRNA miR-371a-3p - A Novel Serum Biomarker of Testicular Germ Cell Tumors: Evidence for Specificity from Measurements in Testicular Vein Blood and in Neoplastic Hydrocele Fluid

“…Once the source of production is eliminated, serum levels are supposed to clear. Similar results have been reported previously [15,16,24], and the present report is a confirmation based on a larger patient number.…”

“…Recently, microRNAs (miRs) have been suggested to be a novel class of serum biomarkers [10,11,12]. Regarding testicular GCT, miRs-371-3 as well as miR-302 and miR-367 represent promising candidates [13,14,15,16,17,18,19,20]. …”

“…They can be measured there by quantitative real time polymerase chain reaction (qPCR). miRs-371-3 and miR-302 have been detected in GCT tissue [14,21,22,23] and elevated serum levels have been documented in several pilot studies [15,16], [24]. miR-371a-3p appears to be the most sensitive marker because it showed the greatest decrease of levels in response to treatment [16,17].…”

Diagnostic markers for germ cell neoplasms: from placental-like alkaline phosphatase to micro-RNAs

“…Tests targeting these specific miRNAs are currently under development. Preliminary studies have already proven great specificity (99-100%) and sensitivity of these tests for the detection of TGCT [100][101][102]. Other body fluids are also suitable for detection of miRNA released by disseminated tumours, e.g.…”

Novel tumor markers in the serum of testicular germ cell cancer patients: a review

“…5 Patients in clinical stage I also showed a decline of circulating miRNAs following orchidectomy. Further research in a series with 80 TGCT patients confirmed the excellent sensitivity of serum miRNAs: 8 an increase of miR-371, miR-372, miR-373, or miR-367 was observed in 98% of the examined TGCT patients; the miRNAs thus outperformed AFP (36%) and HCG (57%). Our own data also confirm the improved sensitivity (85%) and specificity (99%) of miR-371 when compared to AFP (14%) and HCG (37%).…”