One of the kingpins that is associated with chromatin modification for transcriptional activation is the ADA3 (Alteration/Deficiency in Activation 3) protein which is an adaptor component of several lysine acetyltransferase complexes.370 Mirza et al.371 have reported that ADA3 is over expressed in breast cancer patients and as a transcriptional co-activator, human ADA3 (hADA3) interacts with ERα, thereby transactivating its downstream targets leading to breast cancer progression.372. This evidence concerns the gene ESR1 and breast cancer.