[Ovarian Sertoli-Leydig cell tumors: DICER1 hotspot mutations and associated clinicopathological features]

Objective: To investigate DICER1 hotspot mutations in ovarian Sertoli-Leydig cell tumor (SLCT) and its associated clinicopathological features. Methods: Forty-three SLCTs and 40 other sex cord-stromal tumors (SCSTs) diagnosed between 2010 and 2017 at Fudan University Shanghai Cancer Center were examined for somatic DICER1 hotspot mutations by Sanger sequencing. The associations between mutation status and clinicopathological features, including patient age, tumor differentiation and recurrence, were analyzed. Results: Somatic DICER1 mutations were found in 51% (22/43) of SLCTs, while none in the other 40 SCSTs. The most common mutation of DICER1 was p.D1709N in exon 24 (41%, 9/22) and the second most common mutation of DICER1 was p.E1813K in exon 25 (14%, 3/22). A novel frameshift mutation (c.5464delG, p.M1837fs*16) was identified in one SLCT with microcystic pattern. Mutations were more likely to occur in patients under forty years of age (P=0.046), whereas no significant associations were found between DICER1 mutations and clinical symptoms, morphology or tumor recurrence. Conclusions: Somatic DCIER1 hotspot mutations are specifically found in SLCT and may serve as an ancillary marker in differential diagnosis of SLCT from other SCST. The mutations occur more often in young patients (<40 years old). Additional studies are warranted to examine the associations between DICER1 mutations and clinicopathological features and prognosis of SLCT.