HDAC1 and breast cancer: For example, HDAC1 is highly expressed in prostate, gastric, colon, breast, lung, and esophageal cancers; HDAC3 is overexpressed in colon and breast cancers; HDAC6 is upregulated in mammary tumors; HDAC8 is overexpressed in neuroblastoma cells; HDAC11 is found mainly in rhabdomyosarcoma; and HDAC2 has been reported to be elevated in gastric, cervical, and colorectal malignancies [32,33].