[Application of molecular analysis in differential diagnosis of ovarian adult granulosa cell tumors].

Objective: To investigate the application value of molecular detection in the differential diagnosis of ovarian adult granulosa cell tumors (AGCT) by analyzing FOXL2, AKT1 and DICER1 mutations in these tumors. Methods: A total of 48 cases of ovarian sex cord-stromal tumor (SCST) were selected from July 2012 to June 2019 in Beijing Obstetrics and Gynecology Hospital, including 21 adult granulosa cell tumors (AGCT), 15 fibromas/fibrothecomas, 8 Sertoli-Leydig cell tumors (SLCT) and 4 other types of ovarian SCST. Genomic DNA was extracted from the formalin-fixed paraffin-embedded tissue sections. Polymerase chain reaction amplification for FOXL2, AKT1 and DICER1 genes was performed, followed by sequencing using capillary electrophoresis. Fisher exact test was used to compare the prevalence difference of FOXL2, AKT1 and DICER1 mutations among the groups. P< 0.05 was considered significant. Results: Eighteen of the 21 (85.7%) AGCT harbored FOXL2 mutation. Compared with other SCST (13.0%, 3 of 23; including fibromas/fibrothecomas and SLCT), FOXL2 mutation was significantly higher in AGCT ( P< 0.001). In addition, FOXL2 mutation was also detected in one fibrothecoma, two SLCT and two gynandroblastomas. DICER1 mutation was identified in four of eight SLCT, and these cases were moderately to poorly differentiated. FOXL2 mutation was found in one SLCT with DICER1 mutation. There was no DICER1 mutation in other ovarian SCST. No AKT1 mutation was detected in all the patients. Conclusions: FOXL2 mutation is a highly specific biomarker for adult AGCT and may be helpful to resolve problematic cases. Diagnosis should also be taken into consideration of the clinical and histological features as FOXL2 mutation is also found in other SCST. The detection of DICER1 mutation is helpful for the differential diagnosis of ovarian SLCT. Synchronous DICER1 and FOXL2 mutation in the SLCT has been observed, and its significance needs to be further studied.