Frontiers of Medicine

, Volume 5, Issue 4, pp 356–371

Stem cell gene therapy: the risks of insertional mutagenesis and approaches to minimize genotoxicity


DOI: 10.1007/s11684-011-0159-1

Cite this article as:
Wu, C. & Dunbar, C.E. Front. Med. (2011) 5: 356. doi:10.1007/s11684-011-0159-1


Virus-based vectors are widely used in hematopoietic stem cell (HSC) gene therapy, and have the ability to integrate permanently into genomic DNA, thus driving long-term expression of corrective genes in all hematopoietic lineages. To date, HSC gene therapy has been successfully employed in the clinic for improving clinical outcomes in small numbers of patients with X-linked severe combined immunodeficiency (SCID-X1), adenosine deaminase deficiency (ADA-SCID), adrenoleukodystrophy (ALD), thalassemia, chronic granulomatous disease (CGD), and Wiskott-Aldrich syndrome (WAS). However, adverse events were observed during some of these HSC gene therapy clinical trials, linked to insertional activation of proto-oncogenes by integrated proviral vectors leading to clonal expansion and eventual development of leukemia. Numerous studies have been performed to understand the molecular basis of vector-mediated genotoxicity, with the aim of developing safer vectors and lower-risk gene therapy protocols. This review will summarize current information on the mechanisms of insertional mutagenesis in hematopoietic stem and progenitor cells due to integrating gene transfer vectors, discuss the available assays for predicting genotoxicity and mapping vector integration sites, and introduce newlydeveloped approaches for minimizing genotoxicity as a way to further move HSC gene therapy forward into broader clinical application.


gene therapyhematopoietic stem cellsinsertional mutagenesisgenotoxicityinduced pluripotent stem cell

Copyright information

© Higher Education Press and Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  1. 1.Hematology Branch, National Heart, Lung and Blood InstituteNational Institutes of HealthBethesdaUSA