The transgene is composed of a human SFTPC promoter, a human mutant RAF1 cDNA, and an SV40 small T antigen intron and polyadenylation signal. The mutant RAF1 sequence is deleted for the N-terminus and is constitutively active and highly transforming. 3.7 kb of human SFTPC promoter sequences was used to drive transgene expression in lung epithelium. The transgene is highly expressed in lungs as observed by Western blot analysis. The transgene is also weakly expressed in kidneys.