Novel enriched pathways in superficial malignant peripheral nerve sheath tumours and spindle/desmoplastic melanomas

Abstract Superficial malignant peripheral nerve sheath tumour (MPNST) is a rare, soft tissue neoplasm that shares morphological features and some molecular events with spindle/desmoplastic melanoma (SDM). Herein, we sought to identify molecular targets for therapy by using targeted RNA/DNA sequencing and gene expression of key immunological players. DNA and RNA from formalin‐fixed paraffin‐embedded tissue were extracted and processed. Massive high‐throughput deep parallel sequencing was performed with the Oncomine comprehensive panel, enabling detection of relevant single‐nucleotide variants, copy number variations, gene fusions and indels for 143 unique genes on the Ion torrent sequencer for clinical trial research programmes. Gene expression analysis was carried out with a customized 770‐gene expression panel combining markers for 24 different immune cell types and 30 common cancer antigens, including key checkpoint blockade genes analysed with the Ncounter system. Fifty‐one patients (SDM, 16/11; MPNST, 24; male, n = 37; female, n = 16) had sufficient DNA and RNA for testing. NF1 deleterious mutations and/or deep/homozygous deletions were identified in 73% of MPNSTs and 67% of SDMs, with 50% of the mutations involving the RAS‐binding domain. Inactivating/deleterious mutations of TSC1/TSC2 were identified in 40% and 41% of MPNSTs and SDMs, respectively. Activating mutations affecting the EGFR‐like and the negative regulatory domains of NOTCH1 and KDR (VEGFR2)...
Source: The Journal of Pathology - Category: Pathology Authors: Tags: Original Paper Source Type: research