microRNA MARKER FOR TESTICULAR CANCER

NEW YORK (Reuters Health) - The microRNA miR-371a-3p is a new and promising serum marker for germ cell tumors, researchers from Germany report.

"The most exciting finding is the overall sensitivity of 88% of miR-371 in all germ cell tumors with expression of the marker also in the subtype of seminoma," Dr. Klaus-Peter Dieckmann from Albertinen Krankenhaus in Hamburg told Reuters Health by email. "Classical markers have only 50-60% sensitivity."

Those classical markers - alpha-fetoprotein, the beta subunit of human chorionic gonadotropin, and lactate dehydrogenase - are commonly used in the clinical management of testicular germ cell tumors. Recent studies have suggested various microRNAs as new serum biomarkers for germ cell tumors.

Dr. Dieckmann and colleagues evaluated the usefulness of four microRNAs as serum biomarkers in a preliminary study of 50 germ cell tumor patients and 20 controls and in a main study that included 150 patients and 106 controls.

In the preliminary study, all four microRNAs had significantly higher levels of expression in germ cell tumor patients than in controls, and miR-371a-3p had the highest ability to discriminate between patients and controls, the team reports in European Urology, online August 2.

In the main study, miR-371a-3p had a diagnostic sensitivity of 88.7% and specificity of 93.4% for detecting germ cell tumor.

Expression of miR-371a-3p showed better sensitivity and similar specificity for disseminated disease versus localized disease.

The new marker proved superior to the classical germ cell tumor markers in patients with seminoma and non-seminoma germ cell tumors, with an overall sensitivity of 87.8% versus 50.4% for the combined classical biomarkers.

Among 18 clinical stage 2 patients, expression of miR-371a-3p decreased in 12 patients after orchiectomy and dropped to the normal (control) range in most patients after the first cycle of chemotherapy, remaining there during the later course.

Similarly, all but one of nine clinical stage 3 patients showed marked decreases in miR-371a-3p expression after the first cycle of chemotherapy.

All nine patients who relapsed showed elevations of miR-371a-3p expression.

"The supreme sensitivity of this serum biomarker could permit us to reduce radiologic examinations for treatment control and during follow-up," Dr. Dieckmann said. "This would spare much of the toxic irradiation to the young patients with germ cell cancer. Follow-up examinations could become easier and (possibly) cheaper (less computed tomography)."

"The serum miR371 test still requires validation in a larger international study," Dr. Dieckmann said. "But even today, the present data are very much promising. Physicians caring for testis cancer patients should be aware of this exciting new marker test that probably will be introduced into clinical practice by the end of 2017."

"We are currently conducting an international validation study for this test," he said. "By August 2016 we have enrolled as many as 400 patients from Germany, Austria, Switzerland, Hungary, and Italy. The study will go on until the end of this year, and we expect to have about 600 cases for evaluation then. For the lab test (qPCR) we have filed a patent and the lab kit is in preparation as well."

SOURCE: http://bit.ly/2aXKXXd

Eur Urol 2016.