For instance, comparative genomic hybridization (CGH) array analysis from 532 breast tumors indicated a significant copy number gain (23.7% of the cases) for the 7p21‐p15.3 region that encompasses the HDAC9 gene (Mahlknecht et al., 2002; B. Orsetti, data not shown). Here, HDAC9 is linked to breast neoplasm.