HDAC9 and breast cancer: In TN breast cancer patients treated with chemotherapy, rs2285440 (A > C), rs1726599 (C > A) and rs6956139 (C > A) in moderate LD (r2 ≥ 0.38) located in HDAC9 showed associations with two-fold increased HRs (HR 1.92 to 2.41, P <10−3) (Additional file 1: Figure S3b, Additional file 2: Table S4).