In these animals, expression of EGFR, Pcn, and NrgRNAi is driven by ap-Gal4 continuously after the second instar, but the noxious effects of NrgRNAi suppress the tumor phenotype induced by EGFR and Pcn overexpression and are tolerated by the disc cells in which NrgRNAi is expressed. This evidence concerns the gene DHCR7-DT and neoplasm.