title: Targeted exome sequencing profiles genetic alterations in leiomyosarcoma.
abstract: Leiomyosarcoma (LMS) belongs to the class of genetically complex sarcomas and shows numerous, often non-recurrent chromosomal imbalances and aberrations. We investigated a group of LMS using NGS platform to identify recurrent genetic abnormalities and possible therapeutic targets. Targeted exome sequencing of 230 cancer-associated genes was performed on 35 primary soft tissue and visceral (extra-uterine) LMS. Sequence data were analyzed to identify single nucleotide variants, small insertions/deletions (indels), and copy number alterations. Key alterations were further investigated using FISH assay. The study group included patients with median age of 64 years and median tumor size of 7 cm. The primary sites included retroperitoneal/intra-abdominal, extremity, truncal, and visceral. Thirty-one tumors were high grade LMS, while four were low grade. Losses of chromosomal regions involving key tumor suppressor genes PTEN (10q), RB1 (13q), CDH1 (16q), and TP53 (17p) were the most frequent genetic events. Gains mainly involved chromosome regions 17p11.2 (MYOCD) and 15q25-26 (IGF1R). The most frequent mutations were identified in the TP53 gene in 13 of 35 (37%) cases. FISH analysis showed amplification of the myocardin (MYOCD) gene in 5 of 25 (20%) cases analyzed. None of the four low grade LMS showed losses or mutations of PTEN or TP53 genes. Genetic complexity is the hallmark of LMS with losses of important tumor suppressor genes being a common feature. MYOCD, a key gene associated with smooth muscle differentiation, is amplified in a subset of both retroperitoneal and extremity LMS. Further studies are necessary to investigate the significance of gains/amplifications in the development of these tumors.
authors.affiliation: Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Narasimhan P
authors.initials: NP
authors.lastname: Agaram
authors.affiliation: Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Francois
authors.initials: F
authors.lastname: LeLoarer
authors.affiliation: Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Tarik
authors.initials: T
authors.lastname: Silk
authors.affiliation: Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Yun-Shao
authors.initials: YS
authors.lastname: Sung
authors.affiliation: Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Sasinya N
authors.initials: SN
authors.lastname: Scott
authors.affiliation: Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Deborah
authors.initials: D
authors.lastname: Kuk
authors.affiliation: Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Li-Xuan
authors.initials: LX
authors.lastname: Qin
authors.affiliation: Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY.|Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Berger
authors.affiliation: Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Cristina R
authors.initials: CR
authors.lastname: Antonescu
authors.affiliation: Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY.
authors.forename: Samuel
authors.initials: S
authors.lastname: Singer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059472:Exome; D005260:Female; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007890:Leiomyosarcoma / Q000235:genetics* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D017422:Sequence Analysis, DNA / Q000379:methods*