The present invention provides pluripotent and multipotent stem cells, including embryonic stem cells, induced pluripotent stem cells, adult stem cells and other progenitor cells, that have been modified to contain an inducible cancer-specific suicide gene construct that, upon induction, selectively kills stem- or progenitor-cell-derived cancerous cells without significant effect on healthy tissues or other (noncancerous) cells derived from such cells. This suicide gene construct expresses a dominant negative MYC-interfering protein (D-MIP) that acts as a tumor suppressor in cancer cells without significant deleterious effects on healthy cells and tissues. The suicide gene construct can also be used in gene therapies that produce cancers arising in association with the presence of the gene therapy vector and likewise discriminates between killing of cancerous cells and non-cancerous cells modified with a gene therapy vector.