On the stability of sequences inserted into viral genomes

Willemsen, Anouk; Zwart, Mark P

Besides the risks related to retroviral gene therapy, the limited efficiency of in vivo gene transfer poses another obstacle. Replication defective retrovirus vectors are often used in clinical trials but limited since they can only infect a fraction of solid tumor cells (Rainov and Ren 2003) . For the delivery of the transgene in all tumor cells, replication-competent retroviral vectors are a promising alternative. The suitability of murine leukemia virus (MLV)-based vectors for cancer gene therapy has been analyzed in vitro and in vivo by Paar et al. (2007) . They found that the choice of the virus strain, the position of the insert, and the host cells used, can influence the replication kinetics, genomic stability, and transgene expression levels (Paar et al. 2007) .