Retroviral vectors: new solutions to old problems

Gene therapy is a powerful new therapeutic approach that targets disease at the genetic level. While gene therapy encompasses a vast range of molecular practices and methods, viruses are often selected as vectors due to their intrinsic nature and specialized mechanisms of cell entry. The retrovirus family, retroviridae, is particularly useful in gene therapy as a vector for introducing genetic material into cells as they have the capacity to integrate genetic material into the host genome. This characteristic is desirable as it can facilitate stable and long-term expression of the transgene. However, although having the capability to introduce genetic material into deficient cells is highly beneficial, insertional mutagenesis and oncogenesis may result from uncontrolled integration. Such risks are a major safety concern when considering the use of retroviral vectors in a clinical setting. Mal-integration can disrupt the host's genetic integrity resulting in diseases such as cancer. Fortunately, strategies aimed at limiting transgene integration to predetermined sites are in development. Furthermore, modified lentiviral vectors (LVs) have been constructed to transfer genetic elements without any integration. Thus, new solutions that minimize the risk of mal-integration have made retroviral vectors a prospective therapeutic tool which may have a great impact on the landscape of modern medicine.