Genetic engineering has been transformed by CRISPR-Cas9 technology, offering high precision and adaptability in biological research and therapeutic innovation. Originating from a bacterial defense system, CRISPR-Cas9 enables targeted DNA editing through guide RNA-directed Cas9 nuclease activity, allowing gene modification, mutation correction, and disease mechanism analysis. This has opened new avenues in personalized medicine and gene therapy, particularly for cancer and inherited disorders, alongside applications in agriculture. In oncology, CRISPR-Cas9 demonstrates strong potential in oncogene targeting, immune cell engineering, and CAR-T-based immunotherapy, supported by substantial preclinical success. Delivery efficiency is enhanced through systems such as exosomes, liposomes, and nanoparticles, improving stability and tumor targeting. However, clinical translation remains constrained by off-target effects, delivery limitations, and ethical concerns in human genome editing, particularly germline modification. CRISPR shows therapeutic promise for muscular dystrophy, sickle cell disease, and cystic fibrosis. Emerging platforms including base editing, prime editing, and dCas9-based epigenome editing enable precise genome and gene regulation without double-strand breaks, reducing toxicity and expanding therapeutic scope in cancer and genetic diseases. Regulatory frameworks remain heterogeneous, affecting translation. The United States leads in approvals and clinical progress, the European Union emphasizes safety and ethics, China shows rapid expansion in clinical trials, and India remains in early stages due to regulatory and infrastructure constraints. Public perception influences adoption, shaped by misinformation and limited awareness. Persistent gaps in long-term safety, clinical efficacy, and population diversity remain challenges. Overall, CRISPR-Cas9 represents a transformative but carefully regulated platform for advancing biotechnology and medicine.
