Retraction to: Cancer Gene Therapy (2015) 22, 271–77;

https://doi.org/10.1038/cgt.2015.17 published online 10 April 2015

The authors have retracted this article because recent sequence analysis of the hybrid viruses from the chimeric constructs named as CH4 and CH5 has shown that they were contaminated by wild type H-1 virus. All authors agree with this retraction.