Molecular classification of a complex structural rearrangement of the RB1 locus in an infant with sporadic, isolated, intracranial, sellar region retinoblastoma

Autor: Alexander Z. Feldman, Jeffrey R. Leonard, Catherine E. Cottrell, Brent A. Orr, Peter White, Ala K. Shaikhkhalil, Amy Wetzel, Rolla Abu-Arja, Vibhuti Agarwal, Jonathan L. Finlay, Diana S Osorio, Richard K. Wilson, Annie I. Drapeau, Christopher R. Pierson, Sean McGrath, Stephanie LaHaye, Daniel C. Koboldt, Katherine E. Miller, Diana P Rodriguez, Matija Snuderl, Patrick J. Brennan, Kathleen M. Schieffer, Esko A. Kautto, Elaine R. Mardis, Maria Elena Hernandez-Gonzalez, Margaret Shatara, Vincent Magrini, Benjamin J. Kelly, Suzanne Conley, Anthony R. Miller, Daniel R. Boue
Rok vydání: 2021
Předmět:
Zdroj: Acta Neuropathologica Communications, Vol 9, Iss 1, Pp 1-11 (2021)
Acta Neuropathologica Communications
ISSN: 2051-5960
Popis: Retinoblastoma is a childhood cancer of the retina involving germline or somatic alterations of the RB Transcriptional Corepressor 1 gene, RB1. Rare cases of sellar-suprasellar region retinoblastoma without evidence of ocular or pineal tumors have been described. A nine-month-old male presented with a sellar-suprasellar region mass. Histopathology showed an embryonal tumor with focal Flexner-Wintersteiner-like rosettes and loss of retinoblastoma protein (RB1) expression by immunohistochemistry. DNA array-based methylation profiling confidently classified the tumor as pineoblastoma group A/intracranial retinoblastoma. The patient was subsequently enrolled on an institutional translational cancer research protocol and underwent comprehensive molecular profiling, including paired tumor/normal exome and genome sequencing and RNA-sequencing of the tumor. Additionally, Pacific Biosciences (PacBio) Single Molecule Real Time (SMRT) sequencing was performed from comparator normal and disease-involved tissue to resolve complex structural variations. RNA-sequencing revealed multiple fusions clustered within 13q14.1-q21.3, including a novel in-frame fusion of RB1-SIAH3 predicted to prematurely truncate the RB1 protein. SMRT sequencing revealed a complex structural rearrangement spanning 13q14.11-q31.3, including two somatic structural variants within intron 17 of RB1. These events corresponded to the RB1-SIAH3 fusion and a novel RB1 rearrangement expected to correlate with the complete absence of RB1 protein expression. Comprehensive molecular analysis, including DNA array-based methylation profiling and sequencing-based methodologies, were critical for classification and understanding the complex mechanism of RB1 inactivation in this diagnostically challenging tumor.
Databáze: OpenAIRE