MYCN and neuroblastoma: Several other groups have demonstrated that cells treated with all‐trans‐retinoic acid, a retinoid derivative of a chemotherapy drug, express a specific miR signature and reduced levels of MYCN in NB cells (Chen and Stallings, 2007; Laneve et al., 2007; Reynolds and Lemons, 2001; Thiele et al., 1985; Truckenmiller et al., 2001).