HDAC9 and breast cancer: Palmieri et al. reported that the HDAC inhibitor vorinostat prevented the development of 231‐BR (a brain trophic subline of MDA‐MB‐231 human breast cancer cell line) micrometastases by 28% and large metastases by 62% compared with those in vehicle‐treated mice15; Kim et al. observed that the HDAC inhibitor SB939 reduced 4T1‐Br4 (a brain trophic subline of 4T1 mouse breast cancer cell line) metastasis to the brain in vivo and had potent radio‐sensitizing properties in vitro.16