To enhance longlasting antitumor immunity, CG0070 encoded the cDNA for the human cytokine, granulocyte macrophage-colony stimulating factor (GM-CSF) which was selectively produced in Rb pathway–defective tumor cells due to the dependence of the E3 promoter that drives GM-CSF expression on transactivation by E1A. This evidence concerns the gene RB1 and neoplasm.