Gene therapy, in general, encompasses a wide range of treatments that all use genetic material to modify cells to aid in healing. To understand the long-term benefits, it is necessary to be aware of the obstacles to therapeutic intervention and to have a developed approach to overcome them. In addition to, for example, failures in targeting metastatic cells, obstacles also include ethical issues, since approaches in gene therapy result in integration into the individual’s genome and thus the possibility of transmitting genetic changes to the patient’s offspring. As with any new type of therapy, there are serious safety concerns.