FADD and neoplasm: In order to engineer the VNP20009 for tumor-specific delivery of FADD and N-FADD, the coding sequences of mouse FADD and its variant N-FADD were cloned into the plasmid pQE30-NirB (Fig. 4A), in which the expression of the recombinant proteins was driven under the control of a hypoxia-inducible NirB promoter.