Adult granulosa cell tumors (AGCTs) harbor a somatic FOXL2 c.402C>G mutation in ~95% of cases and are mainly surgically removed due to limited systemic treatment effect. In this study, potentially targetable genomic alterations in AGCTs were investigated by whole genome sequencing on 46 tumor samples and matched normal DNA. Copy number variant (CNV) analysis confirmed gain of chromosome 12 and 14, and loss of 22. Pathogenic TP53 mutations were identified in three patients with highest tumor mutational burden and mitotic activity, defining a high-grade AGCT subgroup. Within-patient tumor comparisons showed 29–80% unique somatic mutations per sample, suggesting tumor heterogeneity. A higher mutational burden was found in recurrent tumors, as compared to primary AGCTs. FOXL2-wildtype AGCTs harbored DICER1, TERT(C228T) and TP53 mutations and similar CNV profiles as FOXL2-mutant tumors. Our study confirms that absence of the FOXL2 c.402C>G mutation does not exclude AGCT diagnosis. The lack of overlapping variants in targetable cancer genes indicates the need for personalized treatment for AGCT patients.

For adult granulosa cell tumors (aGCTs), the preferred treatment modality is surgery. Chemotherapy and anti-hormonal therapy are also frequently used in patients with recurrent aGCT. We aimed to review the existing literature on the response to chemotherapy and anti-hormonal therapy in patients with aGCT. Embase and MEDLINE were searched from inception to November 2021 for eligible studies. Objective response rate (ORR) was calculated as the total number of cases with a complete response (CR) or a partial response (PR). Disease control rate (DCR) was defined as the sum of cases with CR, PR or stable disease (SD). A total of 10 studies were included that reported on chemotherapy and 13 studies were included that reported on anti-hormonal therapy. The response rates of the 56 chemotherapy regimens that could be evaluated resulted in an ORR of 30% and DCR of 58%. For anti-hormonal therapy, the results of 73 regimens led to an ORR of 11% and a DCR of 66%. Evidence on systemic therapy in aGCT only is limited. For both chemotherapy and anti-hormonal therapy, the ORR is limited, but the response is considerably higher when patients achieving SD are included. New approaches are needed to provide more evidence and standardize treatment in aGCT.

Adult granulosa cell tumors (aGCTs) represent a rare, hormonally active subtype of ovarian cancer that has a tendency to relapse late and repeatedly. Current serum hormone markers are inaccurate in reflecting tumor burden in a subset of aGCT patients, indicating the need for a novel biomarker. We investigated the presence of circulating tumor DNA (ctDNA) harboring a FOXL2 or TERT promoter mutation in serial plasma samples of aGCT patients to determine its clinical value for monitoring disease. In a national multicenter study, plasma samples (n = 110) were prospectively collected from 21 patients with primary (n = 3) or recurrent (n = 18) aGCT harboring a FOXL2 402C > G and/or TERT (C228T or C250T) promoter mutation. Circulating cell-free DNA was extracted and assessed for ctDNA containing one of either mutations using droplet digital PCR (ddPCR). Fractional abundance of FOXL2 mutant and TERT mutant ctDNA was correlated with clinical parameters. FOXL2 mutant ctDNA was found in plasma of 11 out of 14 patients (78.6%) with aGCT with a confirmed FOXL2 mutation. TERT C228T or TERT C250T mutant ctDNA was detected in plasma of 4 of 10 (40%) and 1 of 2 patients, respectively. Both FOXL2 mutant ctDNA and TERT promoter mutant ctDNA levels correlated with disease progression and treatment response in the majority of patients. FOXL2 mutant ctDNA was present in the majority of aGCT patients and TERT promoter mutant ctDNA has been identified in a smaller subset of patients. Both FOXL2 and TERT mutant ctDNA detection may have clinical value in disease monitoring.

Adult granulosa cell tumors (AGCTs) arise from the estrogen-producing granulosa cells. Treatment of recurrence remains a clinical challenge, as systemic anti-hormonal treatment or chemotherapy is only effective in selected patients. We established a method to rapidly screen for drug responses in vitro using direct patient-derived cell lines in order to optimize treatment selection. The response to 11 monotherapies and 12 combination therapies, including chemotherapeutic, anti-hormonal, and targeted agents, were tested in 12 AGCT-patient-derived cell lines and an AGCT cell line (KGN). Drug screens were performed within 3 weeks after tissue collection by measurement of cell viability 72 h after drug application. The potential synergy of drug combinations was assessed. The human maximum drug plasma concentration (Cmax) and steady state (Css) thresholds obtained from available phase I/II clinical trials were used to predict potential toxicity in patients. Patient-derived AGCT cell lines demonstrated resistance to all monotherapies. All cell lines showed synergistic growth inhibition by combination treatment with carboplatin, paclitaxel, and alpelisib at a concentration needed to obtain 50% cell death (IC50) that are below the maximum achievable concentration in patients (IC50 < Cmax). We show that AGCT cell lines can be rapidly established and used for patient-specific in vitro drug testing, which may guide treatment decisions. Combination treatment with carboplatin, paclitaxel, and alpelisib was consistently effective in AGCT cell lines and should be further studied as a potential effective combination for AGCT treatment in patients.

• In this pilot study, the use of robotic debulking surgery for recurrent granulosa cell tumors was retrospectively analyzed. • Robot-assisted laparoscopic debulking surgery resulted in complete cytoreduction in all patients. • No perioperative complications were reported following robotic cytoreductive surgery. • A minimally invasive approach could reduce the complexity of successive surgeries for granulosa cell tumor relapse.

Objectives: The purpose of the study is to determine whether FOXL2 circulating tumor DNA can be used as a prognostic biomarker and marker for monitoring treatment response in patients with an adult-type granulosa cell tumor (aGCT). Methods: Plasma samples of patients included in the multicenter GRANULOSA study were collected before and after surgery for primary or recurrent aGCT, during follow-up, and during systemic treatment. The presence of ctDNA containing the FOXL2 402C>G mutation was analyzed in 284 samples from 20 primary and 34 recurrent aGCT patients, using digital droplet PCR. Clinical data were retrieved from electronic patient records, and patients were followed through January 2025. Results:FOXL2 mutant ctDNA was detected in 28 of 54 patients (48%). In primary aGCT, recurrences were more frequently seen in patients with detectable ctDNA (33% vs. 18%), and ctDNA remained detectable postoperatively in some cases despite complete cytoreduction. In recurrent aGCT patients, detectable ctDNA was associated with significantly worse overall survival (p = 0.023), and the postoperative presence of ctDNA following complete debulking surgery was significantly associated with a shorter recurrence-free survival (4.7 vs. 11.6 months, p = 0.025). Conclusions:FOXL2 mutant ctDNA could be a prognostic biomarker in aGCT, being associated with worse overall survival in recurrent aGCT patients. In addition, the presence of ctDNA after surgery could reflect the presence of minimal residual disease, negatively impacting the disease course. The implementation of FOXL2 ctDNA measurement in clinical practice may help to identify high-risk aGCT patients.