**Unmasking Intra-Tumoral Heterogeneity and Clonal Evolution in NF1-MPNST**

**Chang-In Moon 1,**†**, William Tompkins 2,**†**, Yuxi Wang 1, Abigail Godec 3, Xiaochun Zhang 1, Patrik Pipkorn 4,5, Christopher A. Miller 5,6, Carina Dehner 7, Sonika Dahiya 5,7 and Angela C. Hirbe 1,5,\***


Received: 6 March 2020; Accepted: 30 April 2020; Published: 1 May 2020

**Abstract:** Sarcomas are highly aggressive cancers that have a high propensity for metastasis, fail to respond to conventional therapies, and carry a poor 5-year survival rate. This is particularly true for patients with neurofibromatosis type 1 (NF1), in which 8%–13% of a ffected individuals will develop a malignant peripheral nerve sheath tumor (MPNST). Despite continued research, no e ffective therapies have emerged from recent clinical trials based on preclinical work. One explanation for these failures could be the lack of attention to intra-tumoral heterogeneity. Prior studies have relied on a single sample from these tumors, which may not be representative of all subclones present within the tumor. In the current study, samples were taken from three distinct areas within a single tumor from a patient with an NF1-MPNST. Whole exome sequencing, RNA sequencing, and copy number analysis were performed on each sample. A blood sample was obtained as a germline DNA control. Distinct mutational signatures were identified in di fferent areas of the tumor as well as significant di fferences in gene expression among the spatially distinct areas, leading to an understanding of the clonal evolution within this patient. These data sugges<sup>t</sup> that multi-regional sampling may be important for driver gene identification and biomarker development in the future.

**Keywords:** NF1; MPNST; genomics; heterogeneity
