TKT and malignant glioma: On the basis of these observations, we developed a phase I clinical trial of vaccination with autologous tumor cells and autologous fibroblasts that are transfected with the TFG-hIL4-Neo-TK to evaluate feasibility, safety, local and systemic immunological response, as well as preliminary therapeutic activity of the approach in patients with recurrent malignant glioma (UPCI95-033) [14].