Direct cell killing by suicide genes.

Cell death can be induced by genetic intervention in a variety of ways. We review genetic prodrug activation therapies using both mammalian and non-mammalian enzyme systems as well as the expression of toxin genes and apoptotic triggers. Targeting of the genetic intervention using both transductional restriction and transcriptional control elements is examined in both in vitro and in vivo systems, and the present state of clinical trials is reviewed.