Primary periosteal cells (Ter119-CD45-CD31-PDPN+ PDGFRα+ cells) were isolated from the tumor-excised calvarial tissues from the scratch-negative groups one week after the implantation of HNM007 cell. Chromatin immunoprecipitation on 100,000 periosteal cells was performed with CUT&RUN Assay Kit (CST, #86652) using antibodies to acetylated histone H3 Lys27 (H3K27ac) (CST,#8173s), H3K4me3 (CST,#9751) and HIF-1α (CST,#36169). Illumina sequencing libraries were prepared using the NEBNext Ultra II DNA Library Prep Kit for Illumina (Cat No. 7645) according to the manufacturer's instructions. Barcoded libraries were run on the NovaSeq 6000 in a PE150 run, and an average of 40 million paired reads were generated per sample.