Microarray identification and characterization of differentially expressed microRNAs in pediatric ovarian immature teratoma

Ovarian immature teratoma (IM) is a type of germinal malignant tumor, affecting children, adolescents and young adults. Event-free survival is below 25% in high-grade IM. Pediatric IM is rare and seldom studied, raising controversial issues such as histopathological standard and lack of specific biomarkers. This study aimed to perform microRNA (miRNA) microarray and identify specific differentially expressed miRNAs in IMs than in other types of ovarian tumors. Our work enables practitioners to optimally exploit relevant characteristics for precise diagnostic and therapeutic strategies in IM. We retrospectively reviewed the medical records of 20 patients with ovarian tumors who were treated at Shanghai Children's Hospital between March 2010 and October 2018. The enrolled patients underwent tumor resection and the samples were collected, including 18 cases using the formalin-fixed, paraffin-embedded (FFPE) approach, of which 2 cases of ovarian cyst, 3 cases of mature teratoma, 6 cases of immature teratoma, 3 cases of yolk sac tumor, 3 cases of juvenile granulosa cell tumor, and 1 case of dysgerminoma; 2 cases were fresh frozen tissue samples preserved in -81℃ environment, including one mature teratoma and one yolk sac tumor. All cases were histologically confirmed by two independent pathologists.