Could miRNAs be used as markers for distinguishing undescended testes from retractile testes? A prospective controlled pilot/exploratory study.

backgroundUndescended testes (UDTs) are common in male infants. Untreated UDT poses risks such as infertility (IF), testicular cancer (TC), and testicular torsion (TT). Retractile testes (RTs) sporadically ascend from the scrotum. UDT requires early surgical correction, whereas RT requires only periodic follow-up. Differentiating these conditions is challenging, making clinical biomarkers potentially useful. The aim of our study was to examine the use of miRNAs as biomarkers in the differential diagnosis of UDT and RT which are difficult to differentiate.

methodsThis prospective pilot/exploratory study included 10 boys with UDT (operated), 9 with RT (followed), and 9 controls. Only palpable (unilateral or bilateral) UDT cases were included, excluding nonpalpable types. To ensure accurate RT diagnosis, initial physician examinations were performed in three positions (supine, semi-supine, standing), followed by a 1-month parental examination (twice daily). Only RT patients whose testes spent > 50% of their time in the scrotum were included. The exclusion criteria also included prior inguinal/scrotal surgery, defective datasets, or unsuitable serum samples. Parent consent and serum samples were collected to evaluate miR-210, miR-34c, and miR-449a expression via real-time PCR.

resultsStatistical analysis revealed no significant difference in miR-34c (p = 0.157) or miR-210 (p = 0.950) expression. However, the miR-449a level differed significantly between the groups (p = 0.033). Dunn-Bonferroni post hoc correction revealed significantly greater miR-449a in the RT group than in the UDT group (p < 0.05). No difference in miR-449a expression was found between the control and UDT groups (p > 0.05). Serum miR-449a demonstrated significant diagnostic potential in differentiating UDT from retractile testis (AUC: 0.822, p = 0.017) with 90.0% sensitivity and 77.8% specificity. These findings suggest that miR-449a could serve as a promising non-invasive biomarker to distinguish true undescended testis from its clinical mimics.

conclusionsSerum miRNA levels represent a potential tool for differentiating UDT from RT. Our pilot/exploratory study partially corroborates this, but comprehensive prospective randomized trials with larger cohorts are essential to definitively clarify miRNA alterations for precise distinction.

trial registrationThis prospective case-control study was registered to clinicaltrials.gov database, 'retrospectively'. The trial registration number is: NCT07315737, the unique protocol ID is: 2022/25.