# In vivo base and prime editing for cancer

Source: https://onco.cc/technologies/in-vivo-gene-editing-cancer/  
OnCo record `in-vivo-gene-editing-cancer` (Technology). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

In vivo base and prime editing would rewrite a cancer's DNA letter by letter inside the body. It works in the liver for inherited disease; nobody has yet corrected a cancer this way in a person.

## Summary

Base editors change a single DNA letter without cutting; prime editors write short new sequences. Both are in the clinic for inherited liver and blood disease, and base editing is used ex vivo to build allogeneic CAR-T cells. Direct in vivo correction of a cancer driver, restoring TP53 or disabling a mutant KRAS allele, had not entered human trials by September 2026: solid-tumour delivery, editing every malignant cell, and the fact that a corrected cell must still out-compete an uncorrected one are all unsolved.

## Fields

- Kind: Technology
- Status: concept
- Last checked: 2026-09-08
- Tags: frontier; radical
- Principle: A catalytically impaired Cas protein fused to a deaminase or reverse transcriptase is guided to a locus and edits it without a double-strand break; delivered by lipid nanoparticle or virus.
- Strengths: Acts on the causal lesion, not a downstream protein; No double-strand breaks, so fewer translocations than nuclease editing; Re-programmable by changing the guide
- Limitations: No in vivo oncology trial yet (2026); Delivery reaches liver far better than solid tumours; Editing a fraction of cells may not change tumour behaviour; Off-target edits are permanent

## Sources

- ClinicalTrials.gov: base editing studies: https://clinicaltrials.gov/search?term=base%20editing

## Connected records

- fronts: [Drug Discovery Platforms](https://onco.cc/fronts/drug-discovery/), [Targeted Therapy](https://onco.cc/fronts/targeted-therapy/)
- technologies: [CRISPR functional genomics](https://onco.cc/technologies/crispr-screens/), [In vivo CAR-T](https://onco.cc/technologies/in-vivo-car-t/), [Programmable DNA-targeting therapeutics](https://onco.cc/technologies/programmable-dna-targeting-therapeutics/)
- targets: [KRAS](https://onco.cc/targets/kras/), [TP53](https://onco.cc/targets/tp53/)
- roadmaps: [Radical oncology: what could change the war by 2035](https://onco.cc/roadmaps/frontier-2035/)

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