Colorectal cancer (CRC) remains a leading cause of cancer mortality worldwide, in part because of genetic heterogeneity and treatment resistance. Among molecular drivers, mutations in the tumor suppressor TP53 are major contributors to loss of genomic integrity and facilitation of tumor progression. Because TP53 dysfunction has broad biological consequences in CRC, restoring or correcting pathogenic TP53 alleles is an attractive precision-oncology objective.
This review focuses on the potential of targeted genome repair—specifically prime editing—to correct TP53 mutations in CRC and thereby achieve functional tumor suppression. The authors synthesize TP53 hotspot biology with recent technological advances and discuss preclinical and translational barriers specific to CRC.
Prime editing is described as a programmable search-and-replace genome engineering approach that does not require two single-stranded DNA breaks. By avoiding double-strand break-dependent repair pathways, prime editing typically produces fewer insertions/deletions (indels) and enables more precise sequence changes compared with traditional CRISPR-Cas9 nuclease approaches. The method uses a Prime Editing Guide RNA (pegRNA) in combination with a Cas-derived nickase fused to a reverse transcriptase to install desired edits.
The review frames prime editing as a next-generation tool for allele-specific correction where high precision and reduced indel formation are prioritized—qualities relevant for editing tumor suppressor genes like TP53 in a therapeutic context.
Several recent systems and engineering strategies are summarized as enhancing prime editing performance. Named advances include PEmax, PE5/PE5max, engineered pegRNAs, twin prime editors, PrimeDel, and PASTE. These variants are reported to increase editing efficiency, expand the range of editable sequence changes, or improve flexibility of the platform. The review highlights that iterative improvements in both editor proteins and pegRNA design underpin the shifting landscape of prime editing applications.
Hotspot TP53 variants discussed as potential prime editing targets include R175H, R248Q/W, R273H/C, and R282W. The review references hotspot-focused studies and organoid experiments suggesting that these common pathogenic substitutions can be targeted for repair. These findings provide a rationale for mutation-specific editing strategies in CRC, although the review does not present new experimental data itself, but synthesizes published work.
The authors emphasize the role of CRC-relevant preclinical models—particularly patient-derived organoids and hotspot mutation studies—to validate prime editing strategies. Organoid systems enable assessment of functional rescue after allele correction and help evaluate phenotypic consequences of TP53 repair in a tissue-relevant context. The review notes that experimental, mechanistic, and translational studies were the focus of the literature search informing these conclusions.
A primary translational challenge identified is delivery. Prime editing systems and associated pegRNAs present substantial cargo size, complicating vector-based delivery. Achieving tumor-specific delivery and sufficient intracellular uptake in heterogeneous CRC tissue are highlighted as major hurdles. The review also calls attention to potential immune recognition of editing cargo, which could limit repeated dosing or provoke adverse responses.
Beyond delivery, CRC-specific barriers include intratumoral heterogeneity that may limit the fraction of cells corrected, variable editing efficiency across different cargoes and contexts, and the persistent risk of off-target edits. These factors collectively pose obstacles to therapeutic translation and necessitate careful preclinical evaluation.
The review underscores the need for optimized delivery strategies, thorough preclinical testing, and rigorous safety monitoring before clinical adoption. Safety endpoints of particular importance include quantification of off-target editing, assessment of indel formation where applicable, immune responses to editing components, and functional validation that corrected TP53 alleles confer tumor-suppressive effects without unintended consequences.
In summary, the authors conclude that prime editing offers promising capabilities for precision oncology in CRC, especially for allele-specific correction of TP53 hotspot mutations. However, they emphasize that substantive technical and translational challenges remain—chiefly delivery, tumor heterogeneity, variable editing performance, immune recognition, and safety risks. The review advocates iterative optimization of prime editing platforms, rigorous organoid and preclinical testing, and development of delivery approaches tailored to CRC as essential steps toward clinical application.
The article presents a synthesis of TP53 biology and recent prime editing advances and positions organoid validation and delivery innovation as central to moving this strategy from concept to clinical testing.