Low mutation burden and frequent loss of CDKN2A/B and SMARCA2, but not PRC2, define premalignant neurofibromatosis type 1-associated atypical neurofibromas.
Neuro Oncol
; 21(8): 981-992, 2019 08 05.
Article
in En
| MEDLINE
| ID: mdl-30722027
ABSTRACT
BACKGROUND:
Neurofibromatosis type 1 (NF1) is a tumor-predisposition disorder caused by germline mutations in NF1. NF1 patients have an 8-16% lifetime risk of developing a malignant peripheral nerve sheath tumor (MPNST), a highly aggressive soft-tissue sarcoma, often arising from preexisting benign plexiform neurofibromas (PNs) and atypical neurofibromas (ANFs). ANFs are distinct from both PN and MPNST, representing an intermediate step in malignant transformation.METHODS:
In the first comprehensive genomic analysis of ANF originating from multiple patients, we performed tumor/normal whole-exome sequencing (WES) of 16 ANFs. In addition, we conducted WES of 3 MPNSTs, copy-number meta-analysis of 26 ANFs and 28 MPNSTs, and whole transcriptome sequencing analysis of 5 ANFs and 5 MPNSTs.RESULTS:
We identified a low number of mutations (median 1, range 0-5) in the exomes of ANFs (only NF1 somatic mutations were recurrent), and frequent deletions of CDKN2A/B (69%) and SMARCA2 (42%). We determined that polycomb repressor complex 2 (PRC2) genes EED and SUZ12 were frequently mutated, deleted, or downregulated in MPNSTs but not in ANFs. Our pilot gene expression study revealed upregulated NRAS, MDM2, CCND1/2/3, and CDK4/6 in ANFs and MPNSTs, and overexpression of EZH2 in MPNSTs only.CONCLUSIONS:
The PN-ANF transition is primarily driven by the deletion of CDKN2A/B. Further progression from ANF to MPNST likely involves broad chromosomal rearrangements and frequent inactivation of the PRC2 genes, loss of the DNA repair genes, and copy-number increase of signal transduction and cell-cycle and pluripotency self-renewal genes.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Neurofibromatosis 1
/
Neurofibrosarcoma
/
Neurofibroma, Plexiform
/
Nerve Sheath Neoplasms
/
Neurofibroma
Type of study:
Prognostic_studies
/
Risk_factors_studies
/
Systematic_reviews
Limits:
Humans
Language:
En
Journal:
Neuro Oncol
Journal subject:
NEOPLASIAS
/
NEUROLOGIA
Year:
2019
Document type:
Article
Affiliation country: