Feasibility Study Intended for In Vivo Retroviral Mediated Gene Transfer of Bladder Urothelium

Current strategies aiming at gene therapy are often focused on ex-vivo manipulation of cells that can be selected for positive gene uptake and which will later be re implanted (Culver et al., 1990; Salvetti et al., 1995). The demands of therapeutic interventions in the field of cancer mostly translate into a requirement to address tumoural cells in vivo. In vivo gene transfer strategies, although conceptually attractive, still need to overcome many technical problems. Difficult access to the target cells and intrinsic impossibility for primary control of gene transfer efficiency represent major limitations. In addition, safety issues have to be considered relating both to diffusion of vectors to other organs or tissues than those of interest and to the consequences of expression of foreign genes in normal tissues. In animal models, introduction and expression of chosen genes in a sufficiently high fraction of tumours cells have been shown to inhibit tumour growth, induce tumour regression, or prevent invasion (Dougherty et al., 1996).