Site-specific CAR transgene insertion into may reduce genotoxic risks in CAR-T cell therapy.
Evidence
This review evaluates viral-vector and CRISPR-related integration risks and summarizes preclinical evidence for safe-harbor loci including AAVS1, TRAC, CCR5, ROSA26, and CLYBL.
Caveat
The proposed safety advantage remains limited by preclinical evidence, editing-efficiency barriers, residual double-stranded DNA toxicity, and the need for long-term surveillance standards.
Simplified
Chimeric antigen receptor (CAR)-T cell therapy has revolutionized oncology by achieving durable remissions in refractory hematologic malignancies. However, emerging reports link this therapy to second primary malignancies, including CAR+ lymphomas and leukemias, driven by insertional mutagenesis from semi-random viral vector integration near oncogenes or tumor suppressor loci. These rare but serious complications underscore the dual challenge of eradicating primary tumors while mitigating delayed genotoxic risks. Conventional CAR-T cell manufacturing, reliant on gamma-retroviral or lentiviral vectors, introduces genomic instability through integration into fragile sites or transcriptionally active regions. CRISPR/Cas9-mediated genome editing further amplifies risks via off-target double-strand breaks and chromosomal rearrangements. This review evaluates (GSHs)-such as AAVS1, TRAC, CCR5, ROSA26 and CLYBL-as loci validated for stable, high-level CAR transgene expression without oncogenic disruption. GSHs meet stringent criteria: distal from cancer-related genes, resistant to epigenetic silencing, and transcriptionally permissive. Preclinical studies demonstrate that site-directed CAR integration into GSHs preserves antitumor efficacy while eliminating malignant transformation risks. Challenges persist in optimizing homology-directed repair efficiency, mitigating residual dsDNA toxicity, and standardizing regulatory frameworks for long-term genomic surveillance. Emerging technologies-base/prime editing, hybrid nucleases, and rigorous monitoring-promise enhanced precision and safety. By reconciling therapeutic innovation with genomic integrity, GSH-engineered CAR-T cells herald a paradigm shift toward precision immunotherapies, offering curative potential while preempting secondary oncogenesis. Collaborative efforts to refine manufacturing, harmonize global standards, and prioritize patient-specific risk stratification will be critical to advancing this transformative approach.
Key numbers
< 1%
SPM Incidence Rate
Estimated incidence rate of SPMs post-CAR-T cell therapy
16 of 449 patients
3.6% of patients
Percentage of CAR-T cell recipients developing secondary malignancies
15.2%
5-year risk for solid tumors
Projected 5-year risk of solid tumors post-CAR-T cell therapy
Full Text
We can’t show the full text here under this license.
