Target Discovery in Head-and-Neck Squamous Cell Carcinoma: Genome-Wide CRISPR Screens Illuminate Therapeutic Resistance and Actionable Dependencies

Head-and-neck squamous cell carcinoma (HNSCC) remains a lethal malignancy with stagnant survival despite advances in surgery, radiotherapy, and systemic therapy. Beyond cetuximab and PD-1 inhibitors, there are only a few targeted options, which benefit only a minority of patients, underscoring the need for new biomarkers and druggable dependencies. Genome-wide clustered regularly interspaced short palindromic repeats (CRISPR) Cas9 screening now enables systematic, high-specificity investigation of gene function to reveal determinants of tumor proliferation, survival, and therapy response. Compared with RNA interference, CRISPR provides cleaner on-target knockout and more interpretable phenotypes, allowing efficient discovery of essential genes and synthetic-lethal interactions. Although the Cancer Dependency Map profiled 89 OSCC/HNSCC lines to nominate baseline dependencies, drug-perturbed states critical for understanding platinum resistance remain underexplored. Only a handful of HNSCC studies have applied genome-wide CRISPR cas9 screening: two mapped core essential genes; two mapped cisplatin resistance and radiation resistance; and others uncovered synthetic-lethal targets, including vulnerabilities to mTOR inhibition, EGFR inhibition, glutamine metabolism inhibition, and host determinants of oncolytic HSV-1 efficacy. This review synthesizes these findings, highlights methodological considerations (library design, coverage, and treatment duration), and integrates complementary functional data to prioritize targets for rational combinations. This review also provides information on the TCGA database and in vivo CRISPR screening that can accelerate precision therapeutics for patients with HNSCC.