CRISPR/Cas9 genome editing: Fueling the revolution in cancer immunotherapy.

The development of genomic editing technologies expands the landscape of T cell engineering for adoptive cell therapy. Among the multiple tools that can be used, CRISPR/Cas9 has been shown to be relatively easy to use, simple to design and cost effective with highly efficient multiplex genome engineering capabilities. Allogeneic universal chimeric antigen receptor (CAR) T cells can be produced by disrupting T cell receptor (TCR) and beta-2-microglobulin (B2M) in CAR T cells or by directly knocking in a CAR at the disrupted TRAC locus. The anti-tumor function can be further boosted by simultaneous ablation of PD-1 and CTLA-4. The anti-tumor activities and safety of TCR-transferred T cells can be improved by knocking out endogenous TCR, which avoids the use of affinity-enhanced TCRs that may lose specificity and cause severe adverse effects. Therefore, CRISPR/Cas9 technology holds enormous promise to advance the field of adoptive cell therapy.