prostate, breast, ovarian and colorectal cancers as well as T-cell acute lymphoid leukemia (T-ALL).20,21 HDAC 3 forms a stable complex with nuclear co-repressor receptor (N-CoR) and enables several biological processes like proliferation, differentiation and apoptosis.21 Fusion proteins from chromosomal rearrangements such as t(12; 21) ETV6-RUNX1 in ALL interfere with HDAC3/N-CoR complex, causing increased proliferation of malignant cells (Figure 2.B). This evidence concerns the gene ETV6 and acute lymphoblastic leukemia.