Figure 1: Different approaches of gene therapy in pancreatic cancers: (a) the vector carries the wild type (WT) version of a tumor suppressor gene lost in the tumor (b) The expression of an oncogene active in the tumor is suppressed by RNA interference or by the expression of a dominant negative form of the oncogene (c) A suicide gene toxic for the tumor cells is delivered in the tumor cells. The suicide gene might activate a non toxic prodrug within the tumor vicinity. A bystander effect might kill the neighboring cells (d) Immunogenic genes are delivered in the tumor cells or in immune cells to trigger tumor-directed immune responses.