Gene Therapy had an interesting series of review articles recently on the potential of mesenchymal (adult) stem cells.
Therapeutic potential of genetically modified mesenchymal stem cells
Stem and progenitor cell-mediated tumor selective gene therapy (abstract)
Endothelial progenitor cells for cancer gene therapy (abstract)
Gene-modified bone marrow cell therapy for prostate cancer (abstract)
And for those who want a little more depth -
Inflammation and tumor microenvironments: defining the migratory itinerary of mesenchymal stem cells (abstract)
Cancer treatments would benefit greatly from targeted therapy, and developing controllable stem cell populations would such a boon for many diseases. Just think - no immune response because they are your own cells, no radiation sickness or adverse drug reactions, and no systemic damage only destruction of the targeted cell population.