Tumor-specific gene expression

For gene therapy to become a realistic treatment modality for cancer, it must be at least as effective and, importantly, less toxic than curent regimes of radio- and chemotherapy. Therefore, the therapeutic gene(s) must only be delivered to, or expressed in, the appropriate target cells. Whilst delivery vehicles with tropisms restricted at the level of the tumor cell surface are still being developed, protocols have been devised which target gene expression specifically to tumor cells, whilst minimizing expression in surrounding cells. Such tumor-cell specific gene expression can be achieved by any combination of localized gene delivery, the use of vectors with selectivity for dividing cells and incorporation of specific transcriptional regulatory sequences to restrict gene expression predominantly to tumor cells.