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Kao EY, Wakeman KM, Wu Y, Gross JM, Chen EY, Ricciotti RW, Liu YJ, Mantilla JG. Prevalence and detection of actionable BRAF V600 and NRAS Q61 mutations in malignant peripheral nerve sheath tumor by droplet digital PCR. Hum Pathol 2022; 129:90-97. [PMID: 36067829 DOI: 10.1016/j.humpath.2022.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 08/26/2022] [Accepted: 08/29/2022] [Indexed: 12/14/2022]
Abstract
Malignant peripheral nerve sheath tumors ( MPNSTs) are aggressive tumors with poor prognosis that do not typically respond well to standard chemotherapy. Recently, point mutations involving BRAF V600E have been demonstrated in a subset of MPNST, offering the possibility of targeted treatment. However, the reported prevalence of these alterations is variable. Mutations involving NRAS, which is also involved in the MAPK/ERK pathway and amenable to targeted inhibitors, have not been well characterized in MPNST. In this study, we validated droplet digital polymerase chain reaction for the detection of BRAF V600E and NRAS Q61 mutations and evaluate the prevalence of BRAF V600E and NRAS Q61 mutations in 79 cases of MPNST, including 45 sporadic, 27 NF-1 associated, and 7 radiation-associated tumors. We detected actionable BRAF or NRAS mutations in 3 of 44 sporadic MPNSTs (6.8%), including 2 BRAF V600 and 1 NRAS Q61 mutations, as well as 1 NRAS Q61 mutation in a tumor that was ultimately considered to represent melanoma. These 3 cases with positive mutations were exclusively in sporadic, high-grade MPNST (FNCLCC grade 3 of 3), with a prevalence of 11.5% in this group (3.8% NRAS Q61 mutations and 7.7% BRAF V600 mutations). None of the tumors associated with NF-1 or prior radiation had detectable mutations in the genes tested. Overall, the prevalence of these alterations offers the possibility of targeted therapy in this aggressive type of sarcoma and suggests the potential benefit of routine clinical testing.
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Affiliation(s)
- Erica Y Kao
- Department of Pathology, Brooke Army Medical Center, San Antonio, TX 78234, USA
| | - Kristina M Wakeman
- Department of Pathology, University of Louisville, Louisville, KY, 40202, USA
| | - Yu Wu
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, 98195, USA
| | - John M Gross
- Department of Pathology, Johns Hopkins University, Baltimore, MD, 21287, USA
| | - Eleanor Y Chen
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, 98195, USA
| | - Robert W Ricciotti
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, 98195, USA
| | - Yajuan J Liu
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, 98195, USA.
| | - Jose G Mantilla
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, 98195, USA.
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