We observed significantly more differentially expressed genes between ACVR1 R206H and ACVR1 WT in the presence of H3.1K27M than without and noted that expression of ACVR1 R206H in nestin-expressing brainstem progenitors upregulated genes that have been previously implicated in the mesenchymal subtype of glioma, namely CD44, Snail2, and Tenascin C22,36,37. This evidence concerns the gene ACVR1 and central nervous system cancer.