In the first, EGFR-Pcn tumor discs were generated from a cross between ap-Gal4,UAS-psqRNAi/CyO;UAS-EGFR,tub-Gal80ts and UAS-CD8:GFP that produces equal numbers of animals with the tumor genotype and non-tumor controls that have the CyO balancer and lack ap-Gal4,UAS-psqRNAi. The gene discussed is DHCR7-DT; the disease is neoplasm.