Gonadal Tumor miRNA Expression in Patients with Differences in Sex Development

Gonadal dysgenesis is caused by abnormal gonadal development and is likely a key mechanism in the pathogenesis of gonadal germ cell tumor (GCT) development, perhaps explaining the increased risk of GCTs in patients with differences in sex development (DSD). Before developing an invasive GCT, the pre-malignant state of germ cell intratubular neoplasia (GCNIS) may develop within dysgenetic gonads of patients with DSD. These lesions could eventually progress to invasive, malignant GCT (50% dysgerminoma, 10% non-dysgerminoma). However, which pre-malignant tumors will transform into GCT and the time to progression from GCNIS to GCT is unknown. Current literature suggests that patients with DSD have a worse prognosis than their male/female counterparts with gonadal GCTs, but data are severely limited, with the largest prospective cohort reporting on just nine patients from across North America. The traditional approach to patients with DSD deemed to be at risk for gonadal malignancy is bilateral gonadectomy early in life. While this certainly prevents gonadal tumors, it also guarantees infertility and hypogonadism at an early age. These are important quality of life issues that are difficult to weigh against the potential risk for malignancy. Despite this aggressive approach utilized historically, scientific data informing best practices remain limited by a fragmented research agenda and lack of standardization of terms, leaving fundamental gaps in knowledge, treatment options and desired outcomes. The identification of patients “at risk” for malignancy has not been adequately studied in prospective large cohorts, thus many patients who may never develop cancer are still subjected to gonadal removal. A more ideal approach would be to spare gonads in patients at lower risk for malignancy in an effort to preserve gonadal function, while simultaneously detecting any malignant transformation at an early stage. If early gonadectomy is not performed, several surveillance regimens have been proposed but proven unsuccessful, and thus evidence-based recommendations for screening patients with DSD for gonadal malignancy are lacking. Literature on serum miRNA levels (specifically miRNA-371) in testicular GCTs shows that this biomarker has improved sensitivity and specificity compared to traditional serum tumor markers in detecting relapse for patients on active surveillance. There are no studies to date examining miRNA in patients with DSD, or evaluating miRNA as a screening tool specifically, but given the excellent sensitivity and specificity reported for testicular GCTs, it is a logical next step to evaluate its role in the DSD population at risk for gonadal GCTs. The objective of this study is to investigate the use of pre-surgical serum miRNA-371 levels as a screening test to predict pre-malignant and malignant transformation in the gonads of patients with DSD. We hypothesize that the sensitivity of miRNA-371 in detecting GCT or GCNIS in patients with DSD will be >85% Methods: This will be a prospective pilot study using prospectively biobanked specimens from a national registry (DSD-TRN) to determine the potential of miRNA-371 to be used as a screening tool to guide gonadectomy for patients with DSD. Patients included will have undergone gonadal surgery (biopsy or gonadectomy) and have serum biobanked at that time. The patient’s pathology report will be reviewed for diagnostic details. Quantitative reverse transcriptase polymerase chain reaction rechniques will be utilized to quantify serum miRNA-371 and these will be correlated with pathologic diagnoses. We will report demographic and clinical characteristics and miRNA-371 relative expression using descriptive statistics. This will be done for the entire cohort and then based on pathology: GCT, GCNIS or neither GCT nor GCNIS. Exploratory between group comparisons will be done using an ANOVA 2 analysis. Given our goal of evaluating miRNA-371 as a screening tool, we will evaluate sensitivity and specificity. We will perform area under the receiver operator characteristic curve (AUC) analyses of the serum miRNA-371 results relative to pathology at gonadectomy, namely any GCT, GCNIS only, and either GCNIS or GCT. This study will allow improved optimization of long-term health for patients with DSD by more precisely identifying which patients would benefit most from gonadectomy and when they would benefit, perhaps delaying this to later in life. Such an approach will decrease healthcare costs, limit exposure to an invasive abdominal procedure and reduce potential morbidity associated with the procedure. The proposed management strategy will improve the lives of patients, families, future partners, and potentially allow for offspring for these patients, with the goal of allowing earlier detection of malignancy and more preservation of gonads.