CSK and neoplasm: To elucidate the role of these pivotal gluconeogenesis genes in HDS-induced tumor growth, we created rasG12V, pepck1RNAi; csk−/− and rasG12V, pepck2RNAi; csk−/− Drosophila models that carry Ras/Src-induced tumors with pepck1 and pepck2 RNAi knockdown, respectively.