Bridging the gap: advanced chromatin biotechnologies for circadian epigenomic profiling in head and neck squamous...

Surgery, radiotherapy and chemotherapy remain the main therapies for treating head and neck cancers, however new modalities have emerged with an emphasis to understand the complexity of the tumor biology. One emerging layer of complexity is the circadian clock, disrupted in many cancers, contributes to pathogenesis and progression due to its crosstalk with cancer pathways. While transcriptional alterations of core clock genes have been described in Head and Neck squamous cell carcinoma (HNSCC), the higher-order epigenetic and chromatin-based mechanisms underlying circadian dysregulation remain poorly defined. In this review, we highlight the potential of several chromatin-based biotechnologies in characterizing circadian clock disruption and identifying epigenetic biomarkers in HNSCC. Powerful assays including Chromatin conformation capture, Chromatin immunoprecipitation, DNA methylation profiling, ATAC-seq and single cell technologies can dissect circadian disruption at multiple regulatory layers. These approaches enable genome-wide mapping of chromatin accessibility, histone modifications, and 3D chromatin organization. Integrating these approaches across HPV-positive (HPV+) and HPV-negative (HPV-) HNSCC provides a framework to determine whether circadian disruption reflects transcriptional deregulation alone or involved structural genome remodeling that actively drives tumor progression. Linking circadian disruption to epigenomic reprogramming in HNSCCs can serve to identify mechanisms of therapeutic resistance and identify vulnerabilities. Advancing chromatin-informed circadian biomarker discovery in HNSCC has the potential to shift precision oncology from static genomic profiling toward dynamic, architecture-based epigenetic regulation.