DKK1 and breast cancer: To further investigate how NBAT1 up-regulated DKK1 via EZH2 in breast cancer, we applied chromatin immunoprecipitation (ChIP)-quantitative real-time PCR (ChIP-qPCR) to analyze trimethylation of histone H3 lysine 27 (H3K27me3) status at DKK1 gene, which is a marker of suppressed chromatin [13-15].