MYC and acute promyelocytic leukemia: Considering the studies which demonstrated that ATRA could induce differentiation decreasing the expression of c-myc oncogene in HL60 promyelocytic leukaemia, and the fact that in some solid cancers an increased expression of c-myc occurs commonly along the tumor progression pathway, some studies have focused on the action of ATRA on c-myc expression of solid cancers, even if still now no RARE element was identified in its sequence.