Existing
tumor markers for
testicular germ cell tumor (TGCT) cannot detect the presence of pure
teratoma. Serum
miRNAs have strong performance detecting other subtypes of TGCT. Previous reports suggest high levels of miR-375 expression in
teratoma tissue. The purpose of this study was to explore the role of serum
miRNA, including miR-375, in detecting the presence of
teratoma at postchemotherapy retroperitoneal
lymph node dissection (PC-RPLND). We prospectively collected presurgical serum from 40 TGCT patients undergoing PC-RPLND (21 with
teratoma at RPLND and 19 with no evidence of disease). We examined the utility of serum miR-375-3p and miR-375-5p by quantitative polymerase chain reaction, and searched for other putative serum
miRNAs with small
RNA sequencing. The area under the receiver operating characteristic curve (AUC) and univariate analyses were utilized to evaluate test characteristics and predictors of
teratoma. Both serum miR-375-3p and miR-375-5p exhibited poor performance (miR-375-3p: 86% sensitivity, 32% specificity, AUC: 0.506; miR-375-5p: 55% sensitivity, 67% specificity, AUC: 0.556).
Teratoma at
orchiectomy was the only predictor of PC-RPLND
teratoma. Small
RNA sequencing identified three potentially discriminatory
miRNAs, but further validation demonstrated no utility. Our results confirm prior reports that serum miR-375 cannot predict
teratoma, and suggest that there may not exist a predictive serum
miRNA for
teratoma.