Suicide gene therapy consists of introduction into tumor cells of a non-mammalian gene encoding an enzyme (such as cytosine deaminase) that converts a non-toxic prodrug (5-fluorocytosine) into a lethal one (5-fluorouracil). In February Gut, V Pierrefite-Carle and colleagues from Faculté de Médecine, Nice, France, show that subcutaneous or intrahepatic injection of suicide gene modified tumor cells can induce an efficient systemic antitumor response in a rat model of metastatic colon carcinoma.

Pierrefite-Carle et al. injected rats with aggressive colon carcinoma cells and then vaccinated these animals with cytosine deaminase (CD) expressing cells followed by 5-fluorocytosine treatment. They observed that either subcutaneous or subcapsular vaccination induced 70% regression in the median volume of the pre-established liver tumor (p=0.001) and abolished tumor dissemination compared with control animals (Gut 2002, 50:387-391).

These data suggests that suicide gene therapy in this form "could represent a powerful alternative therapeutic regimen for...