ATRA induces granulocytic differentiation in APL cells both in vitro and in vivo by activating RAR-α in the PML-RAR-α fusion protein by forcing transcriptional repressor complexes to dissociate from RAR-α [3] and simultaneously degrading PML-RAR-α oncogene products (Figure 2) [40]. The gene discussed is RARA; the disease is acute promyelocytic leukemia.