CRISPR/Cas9 genetic screens in hepatocellular carcinoma gene discovery

The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system is a powerful gene editing tool originated from prokaryotes. The modern CRISPR/Cas9 system allows high-throughput genetic screening to be carried out in vitro and in vivo. The high efficacy and flexibility of CRISPR/Cas9 system allows identification of hepatocellular carcinoma (HCC) related genes in the past decades. Numerous efforts have been applied in the past to improve this system, such as off-target improvement, gRNA efficiency enhancement, and modified Cas9 nuclease for performing visionary base editor screens and epigenetic screens. With these merits, the CRISPR/Cas9 offers tremendous opportunities in various biomedical research and clinical application. Recently, the use of the CRISPR/Cas9 system has also been combined with different technologies, including single-cell sequencing and machine learning, to further understand HCC pathogenesis and explore its utility in gene therapy. This review provides a summary of HCC carcinogenesis CRISPR/Cas9 screens conducted in recent years with different genetic contexts, epidemiological backgrounds, and progression of HCC. Furthermore, this review also provides insight in the CRISPR/Cas9 potentials, current obstacles, and improvement of this system for its future utility in cocktail therapies.