title: Molecular analyses reveal close similarities between small cell carcinoma of the ovary, hypercalcemic type and atypical teratoid/rhabdoid tumor.
abstract: 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.
authors.affiliation: Department of Human Genetics, McGill University, Montreal, Quebec, Canada.|McGill University and Génome Québec Innovation Centre, Montreal, Quebec, Canada.
authors.forename: Somayyeh
authors.initials: S
authors.lastname: Fahiminiya
authors.affiliation: Department of Human Genetics, McGill University, Montreal, Quebec, Canada.
authors.forename: Leora
authors.initials: L
authors.lastname: Witkowski
authors.affiliation: Department of Human Genetics, McGill University, Montreal, Quebec, Canada.|McGill University and Génome Québec Innovation Centre, Montreal, Quebec, Canada.
authors.forename: Javad
authors.initials: J
authors.lastname: Nadaf
authors.affiliation: Department of Human Genetics, McGill University, Montreal, Quebec, Canada.|McGill University and Génome Québec Innovation Centre, Montreal, Quebec, Canada.
authors.forename: Jian
authors.initials: J
authors.lastname: Carrot-Zhang
authors.affiliation: Department of Pediatrics, McGill University, Montreal, Quebec, Canada.
authors.forename: Catherine
authors.initials: C
authors.lastname: Goudie
authors.affiliation: Institute of Neuropathology, University Hospital Münster, Münster, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Hasselblatt
authors.affiliation: Pediatric Hematology and Oncology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Pascal
authors.initials: P
authors.lastname: Johann
authors.affiliation: Division of Pediatric Neuro-Oncology, German Cancer Research Center DKFZ, Heidelberg, Germany.|German Cancer Consortium (DKTK), Core Center Heidelberg, Heidelberg, Germany.
authors.forename: Marcel
authors.initials: M
authors.lastname: Kool
authors.affiliation: Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA.
authors.forename: Ryan S
authors.initials: RS
authors.lastname: Lee
authors.affiliation: Department of Human Genetics, McGill University, Montreal, Quebec, Canada.|Department of Pediatrics, McGill University, Montreal, Quebec, Canada.
authors.forename: Tenzin
authors.initials: T
authors.lastname: Gayden
authors.affiliation: Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA.|Current affiliation: Comprehensive Cancer Center and Department of Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.
authors.forename: Charles W M
authors.initials: CW
authors.lastname: Roberts
authors.affiliation: Department of Pediatrics, Keck School of Medicine of USC, Los Angeles, California, USA.
authors.forename: Jaclyn A
authors.initials: JA
authors.lastname: Biegel
authors.affiliation: Department of Human Genetics, McGill University, Montreal, Quebec, Canada.|Department of Pediatrics, McGill University, Montreal, Quebec, Canada.
authors.forename: Nada
authors.initials: N
authors.lastname: Jabado
authors.affiliation: Department of Human Genetics, McGill University, Montreal, Quebec, Canada.|McGill University and Génome Québec Innovation Centre, Montreal, Quebec, Canada.
authors.forename: Jacek
authors.initials: J
authors.lastname: Majewski
authors.affiliation: Department of Human Genetics, McGill University, Montreal, Quebec, Canada.|Department of Medical Genetics, Lady Davis Institute and Segal Cancer Centre, Jewish General Hospital, McGill University, Montreal, Quebec, Canada.|Department of Medical Genetics, Research Institute, McGill University Health Centre, Montreal, Quebec, Canada.
authors.forename: William D
authors.initials: WD
authors.lastname: Foulkes
mesh_terms: D018288:Carcinoma, Small Cell / Q000235:genetics*; D018284:Cystadenocarcinoma, Serous / Q000235:genetics; D004265:DNA Helicases / Q000235:genetics; D019175:DNA Methylation; D057890:Epigenomics / Q000379:methods; D059472:Exome / Q000235:genetics; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D055106:Genome-Wide Association Study / Q000379:methods; D006801:Humans; D006934:Hypercalcemia / Q000235:genetics*; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics; D010051:Ovarian Neoplasms / Q000235:genetics*; D018335:Rhabdoid Tumor / Q000235:genetics*; D017422:Sequence Analysis, DNA / Q000379:methods; D013724:Teratoma / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics
chemical_list: D009687:Nuclear Proteins; D014157:Transcription Factors; C084108:SMARCA4 protein, human; D004265:DNA Helicases
keywords: ATRT; SCCOHT; SWI/SNF; exome sequencing; methylation