They revealed the high expression levels of these class I HDACs, and IHC results for HDAC1, HDAC2, HDAC3, and HDAC8 were positive in 17 (85%), 20 (100%), 20 (100%), and 17 (85%) of 20 breast cancer cases, respectively (Nakagawa et al., 2007). Here, HDAC2 is linked to breast cancer.