CRISPR enzyme precisely detects and shreds DNA in cancer mutations once considered 'undruggable'

Jennifer Doudna's team has turned a bacterial defense weapon into a precision cancer killer. Six years after she won the Nobel Prize for CRISPR-Cas9, the chemist and her collaborators have unveiled a new enzyme called Cas12a2 that can hunt down and destroy cancer cells carrying mutations long considered impossible to drug—a breakthrough that could transform how doctors treat some of the deadliest malignancies.

The challenge these researchers were tackling is deceptively simple to state but fiendishly difficult to solve. Many cancers are driven by mutations in a tumor suppressor protein called TP53, which is altered in nearly half of all cancer cases and appears in up to 90 percent of ovarian and pancreatic tumors. Yet despite how common these mutations are, not a single approved treatment directly targets them. The reason is structural: these cancer-causing changes lack the binding pockets that traditional drugs need to latch onto, earning them the grim label "undruggable."

Enter Cas12a2. The enzyme works as a molecular scissor that recognizes cancer-specific RNA signatures and, once it finds its target, shreds the chromatin—the DNA and protein mixture that forms chromosomes—within the cancer cell. Unlike conventional drugs that need to grip the mutated protein itself, Cas12a2 simply destroys the cell's DNA at the source.

The team programmed the enzyme with guide RNAs to recognize multiple cancer hallmarks: common mutations in TP53 and EGFR, as well as abnormally high levels of cancer-driving genes like MYC. In laboratory studies, they watched it work with precision. Using fluorescent markers, they confirmed that Cas12a2 activated only when it detected its exact target RNA. When researchers introduced the enzyme into human cancer cells grown in the lab, the effect was dramatic: cancer cells stopped growing, their nuclei fragmented or enlarged from severe DNA damage, and they died. Healthy cells, meanwhile, remained untouched.

The real test came in mice. The team encoded Cas12a2 instructions into mRNA and packaged them inside tiny lipid nanoparticles—essentially microscopic fat bubbles—then injected them into animals with lung and liver cancer. The results were striking. Liver tumor size shrank. Lung cancer progression slowed. The spread of cancer to other parts of the body was delayed. For the first time, a targeted therapy had successfully eliminated TP53 mutations, opening what the researchers describe as a door to "a whole new class of precision therapies."

What makes this discovery particularly hopeful is that it doesn't depend on developing one drug for each mutation. Instead, Cas12a2 provides a programmable platform: researchers can guide the enzyme to recognize any cancer-specific RNA signature they choose, making it adaptable to different tumor types and different patients. The work, published in Nature in 2026, represents the first direct assault on TP53 mutations—a gap in cancer treatment that has persisted for decades despite how frequently these mutations appear in human tumors.

The path from laboratory success to patients is never guaranteed, but the precision and safety demonstrated here suggest that Doudna's new approach could reshape precision oncology, turning some of medicine's most intractable targets into treatable ones.