TOP2B and acute promyelocytic leukemia: Ligand-dependent chromatin recruitment of TOP2B with 17β-estradiol was confirmed in MCF7 cells (Ju et al., 2006; Cowell et al., 2012) and RA induced recruitment of TOPB to the 5′-region of the RARB, was reported by McNamara et al. (2008), who showed that TOP2B-mediated repression of RA-induced genes could lead to RA resistance in APL cell lines.