SUV39H1 was significantly enriched at the PPP2R2B promoter region and the enrichment in BC cells were higher than SV-HUC-1 (Fig. 8F, Fig. S10C), while H3K9me3 modification at the PPP2R2B promoter region was decreased after SUV39H1 knockdown (Fig. 8G). Here, SUV39H1 is linked to breast cancer.