7 980 990 1989 the methodology of using replication incompetent retroviruses for retroviral mediated gene transfer of gene markers is well established correll p h et al pnas usa 86 8912 1989 bordignon c et al pnas usa 86 8912 52 1989 culver r et al pnas usa 88 3155 1991 rill d r et al blood 79 10 2694 700 1992 clinical investigations have shown that there are few or no adverse effects associated with the viral vectors 43 anderson science 256 808 13 1992 however these methods have been limited to transfers of u201c gene markers u201d such as the neomycin gene that merely function as u201c tracking agents u201d for marking malignant cells before and locating malignant cells after reinfusion of bone marrow however the transduction of gene markers confers little clinical benefit to the affected patient who does not receive protection against subsequent relapse rill d r et al blood supra the subject invention eliminates the necessity of the time consuming procedure of transducing cell samples with a selectable marker gene such as neomycin to identify pathologic cells to facilitate subsequent attempts to remove those cells before reinfusion into the patient other vectors are suitable for use in this invention and will be selected for efficient delivery of the nucleic acid encoding the tumor suppressor gene the nucleic acid can be dna cdna or rna the subject invention provides a u201c shotgun u201d procedure whereby the cell sample.