[0135] In one particular embodiment of formula 15, each of X and Y is a hydroxyl group and each of m and n is 5. [0136] In one embodiment, the HDAC inhibitor useful in the methods of the present invention is represented by the structure of formula 16, or a pharmaceutically acceptable salt or hydrate thereof, and a pharmaceutically acceptable carrier or excipient. [0137] wherein each of X and Y are