What can CRISPR actually do against cancer?
CRISPR can attack cancer in several ways: it can directly disable cancer-causing genes, repair tumor-suppressor genes, or engineer immune cells to better recognize and kill tumors. In a 2022 study, researchers used CRISPR to knock down the PD-L1 gene (which helps tumors hide from the immune system) in four mouse models of cancer, significantly slowing tumor growth and metastasis [2]. Another 2023 study restored the TP53 'suicide' gene in prostate cancer cells, causing 40% of the cancer cells to die while leaving healthy cells unharmed [3]. This shows CRISPR can be selective, but the 40% figure also highlights that it's not yet 100% effective.
A particularly clever approach combines CRISPR with existing drugs. A 2025 study used CRISPR to induce DNA damage specifically in cancer cells, then blocked the cells' ability to repair that damage with PARP inhibitors (a class of drugs already used in some cancers). This combination killed cancer cells even when they had a functional BRCA2 gene, which normally makes them resistant to PARP inhibitors alone [4]. This expands the potential use of these drugs to a broader range of cancers.
What's the biggest obstacle to using CRISPR for cancer?
Getting CRISPR components into enough cancer cells inside the body is the single greatest challenge. Tumors are often dense and stiff, making it hard for nanoparticles (the most common delivery vehicle) to penetrate deeply. A 2022 study found that by softening the tumor tissue with a drug that knocks down a stiffness-related protein, they could increase CRISPR delivery efficiency more than tenfold in tumor spheroids [2]. This suggests that simply improving delivery could dramatically boost effectiveness.
Multiple reviews from 2022-2025 agree that viral vectors (like modified viruses) are efficient but carry safety risks and limited cargo capacity, while non-viral methods (like lipid nanoparticles or graphene quantum dots) are safer but less effective [5][6][10]. For example, a 2023 study used graphene quantum dots to deliver CRISPR into prostate cancer cells and tracked the process using the dots' natural fluorescence, but this has only been tested in lab dishes, not in living animals [3]. The field is actively working on better delivery systems, including using probiotics that naturally swim into tumors [9] and metal-coordination micelles that release CRISPR only when triggered by conditions inside cancer cells [11].
How close are we to actual CRISPR cancer treatments for patients?
The only CRISPR therapy that has reached patients in a clinical trial for a genetic disease is NTLA-2002 for hereditary angioedema, which showed a 95% reduction in attacks after a single dose in a small 2024 study [1]. This proves the concept works in humans, but it's not cancer. For cancer, most work is still in lab dishes and animal models, though some CRISPR-engineered CAR-T cells (immune cells modified to attack cancer) have entered early clinical trials [6][7]. A 2022 review noted that CRISPR has been used to create more effective CAR-T cells by knocking out genes that would otherwise cause the immune cells to exhaust or attack healthy tissue [7].
The gap between best-case and typical-case evidence is wide. In the best animal studies, CRISPR combined with other treatments can shrink tumors and prevent metastasis [2][9]. But in typical lab experiments, the efficiency of gene editing in cancer cells varies widely—from 40% cell death in one study [3] to requiring multiple guide RNAs and drug combinations to achieve reliable killing [4]. A 2022 review in Nature Reviews Cancer emphasized that CRISPR has revolutionized how we study cancer genetics, but translating that into therapies faces 'key hurdles' including off-target effects, immune responses, and delivery [8]. Another 2022 review in Molecular Cancer concluded that while CRISPR has 'vast potential,' it is 'not yet ready for widespread clinical use' [7].
About These Sources
This answer is built on 11 peer-reviewed studies — published from 2022 to 2025, 4 from 2024 or later, 10 in Q1 journals, collectively cited 1,204 times — selected as the most relevant from 15 studies that passed quality screening, drawn from 98 papers retrieved from a database of over 500 million.
Sources used in this answer
CRISPR-Cas9 In Vivo Gene Editing of
In a phase 1 trial of 10 patients with hereditary angioedema, a single dose of CRISPR therapy (NTLA-2002) reduced attacks by 95% on average, with no severe adverse events. This is the only in-human CRISPR therapy data among these papers, though for a non-cancer disease.
Enhancing CRISPR/Cas gene editing through modulating cellular mechanical properties for cancer therapy
In four mouse models of cancer, combining CRISPR to knock down PD-L1 with a drug that softens tumor tissue (FAK knockdown) enhanced gene editing more than tenfold in tumor spheroids and significantly inhibited tumor growth and metastasis.
In Vitro Prostate Cancer Treatment via CRISPR‐Cas9 Gene Editing Facilitated by Polyethyleneimine‐Derived Graphene Quantum Dots
Using graphene quantum dots to deliver CRISPR into prostate cancer cells in the lab, researchers restored the TP53 tumor-suppressor gene, causing 40% of cancer cells to die while leaving healthy cells unaffected.
Combining Multiplexed CRISPR/Cas9-Nickase and PARP Inhibitors Efficiently and Precisely Targets Cancer Cells
Combining CRISPR-Cas9 nickase (which cuts only one DNA strand) with PARP inhibitors killed cancer cells in culture, xenografts, and patient-derived organoids, even when the BRCA2 gene was functional—expanding the potential use of PARP inhibitors.
Overcoming the Delivery Challenges in CRISPR/Cas9 Gene Editing for Effective Cancer Treatment: A Review of Delivery Systems
A 2025 review of delivery systems for CRISPR in cancer treatment concluded that viral vectors are efficient but have safety and cargo limitations, while non-viral methods like extracellular vesicles are safer but less effective.
Gene editing in cancer therapy: overcoming drug resistance and enhancing precision medicine
A 2025 review highlighted that CRISPR can overcome drug resistance, enhance chemotherapy sensitivity, and improve CAR-T cell therapy, but noted that off-target effects, immune responses, and delivery remain key hurdles.
Current applications and future perspective of CRISPR/Cas9 gene editing in cancer
A 2022 review in Molecular Cancer (414 citations) detailed CRISPR's use in cancer gene screening, animal models, and CAR-T cell engineering, concluding that delivery and off-target effects are the main barriers to clinical translation.
CRISPR in cancer biology and therapy
A 2022 review in Nature Reviews Cancer (390 citations) stated that CRISPR has transformed cancer research by enabling large-scale genetic screens and new therapeutic approaches, but that clinical application faces significant challenges.
Design of a self-driven probiotic-CRISPR/Cas9 nanosystem for sono-immunometabolic cancer therapy
In a mouse study, a probiotic (Lactobacillus) carrying a CRISPR system was used to knock down the IDO1 gene in tumors, which combined with ultrasound to generate an immune response that inhibited tumor growth and protected against lung metastasis.
Engineered Nanomaterials to Potentiate CRISPR/Cas9 Gene Editing for Cancer Therapy
A 2023 review on engineered nanomaterials for CRISPR delivery concluded that non-viral nanoformulations can improve safety, efficiency, and specificity, but most are still in preclinical development.
Metal coordination micelles for anti-cancer treatment by gene-editing and phototherapy
In a mouse tumor model, a metal-coordination micelle system delivered CRISPR to knock out the MTH1 and APE1 genes, which combined with photodynamic therapy inhibited tumor growth.