Drosophila melanogaster is emerging as a useful system to model cancer. Using a luciferase reporter gene, tumor growth in Drosophila gut tissue in response to oncogene activation can be quantified. Our goal is to develop new Drosophila models of colon cancer. We performed a targeted screen of genes in cancer pathways to identify candidates that show excessive tissue growth when expressed in adult gut tissue. Cancer genes affecting the PI3 kinase and receptor tyrosine kinase signaling pathways produced significant tissue growth relative to negative controls. Genes affecting G1 and G1/S phases of the cell cycle also produced a significant increase in tissue growth, whereas genes affecting G2 and M phases had little effect. Candidate genes from this study will be used for future experiments to understand why cells transformed by one cancer pathway or another may respond differently to chemotherapies.