HDAC2 and cancer: Some of the proteins have well-established roles in BC, such as protein encoded by the CHD4 gene, which can promote BC growth and progression27, protein encoded by the RBB4 gene, whose high expression levels associate with poor BC prognosis28 and protein encoded by the HDAC2 gene, which is found overexpressed in different cancers and considered an important target in cancer therapy29 (Supplementary Note 3).