To further explore the epigenetic modulation of RGS2 activation by PCI-24781, we performed quantitative chromatin immunoprecipitation (qChIP) assays with specific antibodies against H3 acetylation to examine five promoter regions of RGS2 in MDA-MB-231 and T-47D, as well as the murine breast cancer cell 4T1 cells after PCI-24781 treatment. This evidence concerns the gene RGS2 and breast cancer.