**5. Conclusions**

Significant intra-tumoral heterogeneity exists and may be a barrier to our ability to improve outcomes in patients with NF1-MPNST. These data sugges<sup>t</sup> that multi-regional sampling may be necessary to understand clonal evolution, and for driver gene identification and biomarker development in the future.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2073-4425/11/5/499/s1, Supplemental Table S1: Comprehensive Genomic Information for Single Nucleotide Variants.

**Author Contributions:** Conceptualization, A.C.H.; Formal analysis, C.-I.M., Y.W., C.D., and A.G.; Funding acquisition, A.C.H.; Investigation, C.-I.M., W.T., C.D., Y.W. and X.Z.; Resources, A.G., X.Z., P.P. and S.D.; Software, C.-I.M.; C.A.M. Supervision, A.C.H.; Writing—original draft, C.-I.M. and W.T.; Writing—review & editing, Y.W., C.D., A.G., X.Z., P.P., S.D., C.A.M. and A.C.H. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was funded by the St. Louis Men's Group Against Cancer. Hirbe is funded by a Francis Collins Scholar Award through NTAP.

**Conflicts of Interest:** The authors declare no potential conflicts of interest.
