[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.目的： 探讨常见卵巢性索-间质肿瘤中FOXL2、AKT1、DICER1的突变情况及分子病理检测在卵巢粒层细胞瘤鉴别诊断中的应用价值。 方法： 收集2012年7月至2019年6月间首都医科大学附属北京妇产医院组织学诊断为卵巢成人型粒层细胞瘤21例，卵巢纤维瘤/卵泡膜纤维瘤15例，卵巢支持-间质细胞瘤8例，卵巢其他类型性索-间质肿瘤4例的患者资料和存档切片。从中性甲醛固定、石蜡包埋组织中提取基因组DNA，采用PCR法扩增FOXL2、AKT1、DICER1，并采用毛细管电泳法分析突变情况。应用Fisher确切概率法对各组中FOXL2、AKT1、DICER1突变差异进行统计学分析。 结果： 85.7%（18/21）成人型粒层细胞瘤中存在FOXL2突变，与其他卵巢性索-间质肿瘤（13.0%，3/23；只包括卵巢纤维瘤/卵泡膜纤维瘤及支持-间质细胞瘤）相比，FOXL2突变在成人型粒层细胞瘤中明显增高，差异有统计学意义（P<0.001）。1例卵泡膜纤维瘤、2例支持-间质细胞瘤及2例两性母细胞瘤中也检测到FOXL2突变。4例卵巢支持-间质细胞瘤中存在DICER1突变，主要见于中-低分化病例中。1例携带DICER1突变的支持-间质细胞瘤中存在FOXL2突变。其他卵巢性索-间质肿瘤均未检测到DICER1突变。入组病例中均未检测到AKT1突变。 结论： FOXL2突变是成人型粒层细胞瘤特异度较高的分子标志物，适用于疑难病例的鉴别诊断，但因其也可见于其他性索-间质肿瘤中，鉴别时需要结合临床表现及组织学特征。DICER1突变检测有助于卵巢支持-间质肿瘤的鉴别诊断，研究中观察到DICER1与FOXL2突变共存现象，其意义有待进一步研究。.