Molecular Characterization of a Patient's Small Cell Carcinoma of the Ovary of the Hypercalcemic Type.
ABSTRACT: Small cell carcinoma of the ovary of the hypercalcemic type (SCCOHT) is a very rare tumor type that mainly affects young women. We report a 21-year old woman with SCCOHT. The patient initially presented with stage T3AN1MX disease and treated with surgery. The patient then received 8 cycles of multi-agent chemotherapy including cisplatin, bleomycin, cyclophosphamide, doxorubicin, and etoposide. Upon relapse, the patient underwent total abdominal hysterectomy, followed by chemotherapy with gemcitabine. The patient subsequently received radiation therapy and chemotherapy with bevacizumab, irinotecan and docetaxel. She passed away approximately 5 months after the second surgery and with her prior permission an immediate autopsy was performed. We examined the gene expression and copy number profiles of the tumor tissue samples obtained from the autopsy and compared them to normal ovary tissues. Our results indicated that although this tumor did not harbor chromosomal abnormalities nor gene copy number changes, there were significant gene expression changes in a number of genes/pathways. More than 5,000 genes showed significant differential expression in the tumor when compared to normal ovary tissue. Pathway enrichment analysis further identified several pathways/processes including the Vitamin D receptor signaling and the hedgehog signaling pathways to be significantly dysregulated. The gene expression profiling also suggests a number of agents such as pazopanib, bortezomib, 5-azacytidine, and PARP inhibitors as treatment options to possibly explore in future trials against this disease.
Project description:Small-cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is a rare but highly undifferentiated, aggressive malignancy that primarily affects young women. Due to its early onset, unclear familial history and vague presenting symptoms, most SCCOHT patients present late with advanced disease. The prognosis is extremely poor, with <10% disease-free survival for advanced stages. Although several therapeutic regimens have been proposed, to date there is no consensus on the optimal strategy. Here, we describe a successful case of advanced-stage SCCOHT of the left ovary treated with cytoreductive surgery, semi-intense chemotherapy, high-dose consolidative chemotherapy, autologous hematopoietic stem cell transplantation and pelvic radiation with long-term survival. Given the almost universal mortality of advanced SCCOHT in long-term follow-up, we believe this case highlights the importance of prompt diagnosis when a young patient presents with abdominal swelling and hypercalcemia as well as early, aggressive, combined modality treatment. This case is also especially remarkable given the patient underwent fertility preservation surgery, which is not recommended by most of the current literature. However, as therapies improve and more young patients may survive SCCOHT, the question of fertility will increase in relevance. We believe the pros and cons of conservation should be discussed in detail with the patient.
Project description:Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is an aggressive malignancy that occurs in young women, is characterized by recurrent loss-of-function mutations in the SMARCA4 gene, and for which effective treatments options are lacking. The aim of this study was to broaden the knowledge on this rare malignancy by reporting a comprehensive molecular analysis of an independent cohort of SCCOHT cases. We conducted Whole Exome Sequencing in six SCCOHT, and RNA-sequencing and array comparative genomic hybridization in eight SCCOHT. Additional immunohistochemical, Sanger sequencing and functional data are also provided. SCCOHTs showed remarkable genomic stability, with diploid profiles and low mutation load (mean, 5.43 mutations/Mb), including in the three chemotherapy-exposed tumors. All but one SCCOHT cases exhibited 19p13.2-3 copy-neutral LOH. SMARCA4 deleterious mutations were recurrent and accompanied by loss of expression of the SMARCA2 paralog. Variants in a few other genes located in 19p13.2-3 (e.g., PLK5) were detected. Putative therapeutic targets, including MAGEA4, AURKB and CLDN6, were found to be overexpressed in SCCOHT by RNA-seq as compared to benign ovarian tissue. Lastly, we provide additional evidence for sensitivity of SCCOHT to HDAC, DNMT and EZH2 inhibitors. Despite their aggressive clinical course, SCCOHT show remarkable inter-tumor homogeneity and display genomic stability, low mutation burden and few somatic copy number alterations. These findings and preliminary functional data support further exploration of epigenetic therapies in this lethal disease.
Project description:OBJECTIVE:Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is an aggressive tumor, with long term survival at ~30% in early stage disease. SCCOHT is caused by germline and somatic SMARCA4 mutations, but the effect of the mutation type on patients remains unknown. Furthermore, the rarity of SCCOHT has resulted in varied treatment, with no standardized protocols. We analyzed 293 cases to determine the effect of treatment modalities and SMARCA4 mutations on patient diagnosis and outcome. METHODS:In 293 SCCOHT patients we collected information on age and stage at diagnosis, treatment modality (surgery, chemotherapy, radiotherapy, and/or high-dose chemotherapy with autologous stem cell rescue (HDC-aSCR)), SMARCA4 mutation origin (germline/somatic), and overall survival. Cox analysis and log-rank tests were performed on 257 cases with available survival data. RESULTS:The strongest prognostic factors were stage at diagnosis (p=2.72e-15) and treatment modality (p=3.87e-13). For FIGO stages II-IV, 5-year survival was 71% for patients who received HDC-aSCR, compared to 25% in patients who received conventional chemotherapy alone following surgery (p=0.002). Patients aged ?40 had a worse outcome than younger patients (p=0.04). Twenty-six of 60 tested patients carried a germline SMARCA4 mutation, including all patients diagnosed <15years; carriers presented at a younger age than non-carriers (p=0.02). CONCLUSIONS:Stage at diagnosis is the most significant prognostic factor in SCCOHT and consolidation with HDC-aSCR may provide the best opportunity for long-term survival. The large fraction of SMARCA4 germline mutations carriers warrants genetic counseling for all patients.
Project description:Inactivating mutations in SMARCA4 (BRG1), a key SWI/SNF chromatin remodelling gene, underlie small cell carcinoma of the ovary, hypercalcemic type (SCCOHT). To reveal its druggable vulnerabilities, we perform kinase-focused RNAi screens and uncover that SMARCA4-deficient SCCOHT cells are highly sensitive to the inhibition of cyclin-dependent kinase 4/6 (CDK4/6). SMARCA4 loss causes profound downregulation of cyclin D1, which limits CDK4/6 kinase activity in SCCOHT cells and leads to in vitro and in vivo susceptibility to CDK4/6 inhibitors. SCCOHT patient tumors are deficient in cyclin D1 yet retain the retinoblastoma-proficient/p16INK4a-deficient profile associated with positive responses to CDK4/6 inhibitors. Thus, our findings indicate that CDK4/6 inhibitors, approved for a breast cancer subtype addicted to CDK4/6 activation, could be repurposed to treat SCCOHT. Moreover, our study suggests a novel paradigm whereby critically low oncogene levels, caused by loss of a driver tumor suppressor, may also be exploited therapeutically.
Project description:Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT), is a rare and understudied cancer with a dismal prognosis. SCCOHT's infrequency has hindered empirical study of its biology and clinical management. However, we and others have recently identified inactivating mutations in the SWI/SNF chromatin remodeling gene SMARCA4 with concomitant loss of SMARCA4 protein in the majority of SCCOHT tumors.(1-4) Here we summarize these findings and report SMARCA4 status by targeted sequencing and/or immunohistochemistry (IHC) in an additional 12 SCCOHT tumors, 3 matched germlines, and the cell line SCCOHT-1. We also report the identification of a homozygous inactivating mutation in the gene SMARCB1 in one SCCOHT tumor with wild-type SMARCA4, suggesting that SMARCB1 inactivation may also play a role in the pathogenesis of SCCOHT. To date, SMARCA4 mutations and protein loss have been reported in the majority of 69 SCCOHT cases (including 2 cell lines). These data firmly establish SMARCA4 as a tumor suppressor whose loss promotes the development of SCCOHT, setting the stage for rapid advancement in the biological understanding, diagnosis, and treatment of this rare tumor type.
Project description:Small cell carcinoma of the ovary of hypercalcemic type (SCCOHT) is an extremely rare, aggressive cancer affecting children and young women. We identified germline and somatic inactivating mutations in the SWI/SNF chromatin-remodeling gene SMARCA4 in 75% (9/12) of SCCOHT cases in addition to SMARCA4 protein loss in 82% (14/17) of SCCOHT tumors but in only 0.4% (2/485) of other primary ovarian tumors. These data implicate SMARCA4 in SCCOHT oncogenesis.
Project description:Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is a rare but extremely lethal malignancy that mainly impacts young women. SCCOHT is characterized by a diploid genome with loss of SMARCA4 and lack of SMARCA2 expression, two mutually exclusive ATPases of the SWI/SNF chromatin-remodeling complex. We and others have identified the histone methyltransferase EZH2 as a promising therapeutic target for SCCOHT, suggesting that SCCOHT cells depend on the alternation of epigenetic pathways for survival. In this study, we found that SCCOHT cells were more sensitive to pan-HDAC inhibitors compared with other ovarian cancer lines or immortalized cell lines tested. Pan-HDAC inhibitors, such as quisinostat, reversed the expression of a group of proteins that were deregulated in SCCOHT cells due to SMARCA4 loss, leading to growth arrest, apoptosis, and differentiation in vitro and suppressed tumor growth of xenografted tumors of SCCOHT cells. Moreover, combined treatment of HDAC inhibitors and EZH2 inhibitors at sublethal doses synergistically induced histone H3K27 acetylation and target gene expression, leading to rapid induction of apoptosis and growth suppression of SCCOHT cells and xenografted tumors. Therefore, our preclinical study highlighted the therapeutic potential of combined treatment of HDAC inhibitors with EZH2 catalytic inhibitors to treat SCCOHT.
Project description:A 12-yr-old normocalcemic female treated for a ruptured ovarian juvenile granulosa cell tumor at an outside hospital presented for exploratory laparotomy and gross surgical debulking of pelvic recurrence. Morphologically, the tumor was composed of sheets and nests of small blue cells forming cysts of various sizes and focal mucinous differentiation. Epithelial membrane antigen (EMA), patchy inhibin, and strong and diffuse p53 immunoreactivity were also observed. A revised diagnosis of mixed sex cord stromal tumor with heterologous elements was favored because of the inhibin immunoreactivity. Targeted next-generation sequencing of the tumor revealed a SMARCA4 c.1141C>T, p.Arg381Ter (NM_001128849.1) nonsense mutation and an in-frame 18-bp TP53 deletion (c.594_611del18, p.Gly199_Glu204del, NM_001126112.2). Cytogenetic analysis revealed a normal 46,XX karyotype, and OncoScan single-nucleotide polymorphism array analysis demonstrated copy-neutral loss of heterozygosity (CN-LOH) of 19p13.3-19p13.2 and mosaic CN-LOH of 17p13.3-p11.2 encompassing the SMARCA4 and TP53 loci, respectively. Subsequent germline SMARCA4 sequencing confirmed a heterozygous SMARCA4 p.Arg381Ter mutation. In lieu of the molecular findings, the diagnosis was amended to small cell carcinoma of the ovary, hypercalcemic type (SCCOHT). The patient was treated aggressively with paclitaxel, carboplatin, and bevacizumab. She received an autologous stem cell transplant but died 5 mo after SCCOHT diagnosis secondary to complications of the transplant. This case expands the morphologic, immunophenotypic, and genomic spectrum of SCCOHT and highlights how multimodal molecular analysis can assist with the diagnosis and clinical management of SCCOHT patients.
Project description:Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is the most common undifferentiated ovarian malignancy diagnosed in women under age 40. We and others recently determined that germline and/or somatic deleterious mutations in SMARCA4 characterize SCCOHT. Alterations in this gene, or the related SWI/SNF chromatin remodeling gene SMARCB1, have been previously reported in atypical teratoid/rhabdoid tumors (ATRTs) and malignant rhabdoid tumors (MRTs). To further describe the somatic landscape of SCCOHT, we performed whole exome sequencing on 14 tumors and their matched normal tissues and compared their genomic alterations with those in ATRT and ovarian high grade serous carcinoma (HGSC). We confirmed that SMARCA4 is the only recurrently mutated gene in SCCOHT, and show that recurrent allelic imbalance is observed exclusively on chromosome 19p, where SMARCA4 resides. By comparing genomic alterations between SCCOHT, ATRT and HGSC, we demonstrate that SCCOHTs, like ATRTs, have a remarkably simple genome and harbor significantly fewer somatic protein-coding mutations and chromosomal alterations than HGSC. Furthermore, a comparison of global DNA methylation profiles of 45 SCCOHTs, 65 ATRTs, and 92 HGSCs demonstrates a strong epigenetic correlation between SCCOHT and ATRT. Our results further confirm that the genomic and epigenomic signatures of SCCOHT are more similar to those of ATRT than HGSC, supporting our previous hypothesis that SCCOHT is a rhabdoid tumor and should be renamed MRT of the ovary. Furthermore, we conclude that SMARCA4 inactivation is the main cause of SCCOHT, and that new distinct therapeutic approaches should be developed to specifically target this devastating tumor.