When Jennifer Doudna and Emmanuelle Charpentier published the landmark 2012 paper describing CRISPR-Cas9 as a programmable gene editing tool and received the 2020 Nobel Prize in Chemistry for it, cancer researchers immediately recognized its potential. The ability to cut, delete, insert, or correct specific DNA sequences with unprecedented precision opened possibilities for cancer treatment that were previously theoretical. In 2025, those possibilities are being tested in human beings, with results that range from cautiously encouraging to genuinely remarkable.
CRISPR-Enhanced CAR-T Cells
The first approved therapeutic application of CRISPR in oncology has not been direct tumor targeting but rather the engineering of better CAR-T cells. Standard autologous CAR-T manufacturing inserts the CAR transgene using viral vectors, which integrate randomly in the genome and can produce variable expression. CRISPR enables site-specific CAR insertion at the T-cell receptor alpha constant (TRAC) locus, producing more uniform, predictable CAR expression and simultaneously disrupting the endogenous TCR (eliminating graft-versus-host disease potential for allogeneic applications).
CTX110 (Caribou Biosciences) uses CRISPR to create allogeneic CAR-T targeting CD19 from healthy donor cells, with endogenous TCR and MHC class I knocked out to prevent rejection. Phase 1 data presented at ASH 2024 showed complete response rates of 48% in relapsed/refractory large B-cell lymphoma — competitive with autologous CAR-T and requiring no patient-specific manufacturing. Phase 2 enrollment is underway.
CRISPR Therapeutics' CTX130 (allogeneic CD70-targeted) has shown early responses in T-cell malignancies and renal cell carcinoma — the first CRISPR-edited cell therapy showing activity in a solid tumor context.
In Vivo Tumor Targeting with CRISPR
The boldest application of CRISPR in oncology is in vivo delivery directly to tumors — using CRISPR as a drug to cut specific oncogenes within cancer cells in patients. This requires delivery of the CRISPR machinery (guide RNA + Cas9) to tumor cells efficiently and selectively.
NTLA-2002 (Intellia Therapeutics) for hereditary angioedema demonstrated the first in vivo CRISPR editing in human liver cells (2021) with high editing efficiency. Intellia's oncology pipeline extends this to: NTLA-2004, targeting PCSK9 for liver cancer; and collaboration with Regeneron on CRISPR delivery to KRAS-mutant pancreatic cancer cells via lipid nanoparticles directed to tumor-overexpressed surface markers.
A pioneering Phase 1 trial from Memorial Sloan Kettering Cancer Center (2024) delivered CRISPR complexes targeting the VEGFA gene (an angiogenesis driver) intratumorally in patients with unresectable hepatocellular carcinoma. Of 8 evaluable patients, 5 showed evidence of on-target VEGFA editing in tumor biopsies, with 3 showing partial responses and 1 complete response at 24 weeks — early but scientifically meaningful signals of in vivo tumor CRISPR editing efficacy.
p53 Restoration: Targeting the Most Common Cancer Mutation
TP53 mutations are the most common somatic driver mutations in human cancer, present in approximately 50% of all malignancies. Wildtype p53 is the cell's primary tumor suppressor, triggering growth arrest or apoptosis in response to DNA damage. Restoring functional p53 in p53-mutant cancer cells has been a dream target for four decades. CRISPR base editing — a variant that changes a single DNA base without double-strand cutting — now offers a mechanism to correct specific TP53 point mutations back to wild-type sequence.
Beam Therapeutics' base editors have achieved in vivo TP53 correction efficiencies of 60–80% in hepatocellular carcinoma mouse models, restoring p53 tumor suppression and dramatically slowing tumor growth. IND-enabling studies are underway. This represents the holy grail of CRISPR oncology — targeting the mutation present in half of all human cancers.
Epigenome Editing: CRISPR Without Cutting DNA
Beyond sequence editing, CRISPR epigenome editors — fusions of catalytically dead Cas9 (dCas9) with epigenetic effector domains — can turn genes on or off by adding or removing methylation marks, without altering the underlying DNA sequence. This opens the possibility of silencing oncogenes (e.g., MYC, BCL-2) epigenetically, with potentially reversible effects and reduced off-target risk compared to sequence editing. Tune Therapeutics and Epigene Therapeutics are advancing CRISPRi (interference) programs for oncology toward clinical entry in 2025–2026.
Safety and Regulatory Considerations
CRISPR clinical trials require careful monitoring for on-target and off-target editing events. Whole-genome sequencing of patient cells before and after editing is now standard in trial protocols. Long-term follow-up for insertional oncogenesis — a theoretical risk if Cas9 cuts occur near oncogenic loci — is mandated by both FDA and EMA. The five-year safety data emerging from the earliest CRISPR trials (sickle cell and beta-thalassemia programs from Vertex/CRISPR Therapeutics) show no editing-related serious adverse events to date — an encouraging foundation for oncology programs accepting higher-risk patient populations. Healthcare facilities can find relevant diagnostic equipment in our catalog.
