Integrating Whole-Exome Sequencing with Clinical and Histopathological Endpoints in Chemoprevention Studies: A Framework for Mechanistically Informed Prevention Trials

Abstract The integration of whole-exome sequencing (WES) with classical clinical and histopathological endpoints represents a paradigm shift in cancer chemoprevention trial design, enabling mechanistically informed patient stratification and molecular monitoring of intervention efficacy. This review examines the state-of-the-art in multi-endpoint chemoprevention studies, with emphasis on (1) correlating somatic mutations detected via WES with histopathological dysplasia grade and regression, (2) designing chemoprevention trials with composite endpoints combining molecular, histological, and clinical measures, and (3) strengthening causal inference regarding biomarker-guided interventions through mediation analysis, reverse validation, and mechanistic studies. We synthesize evidence from landmark studies including the Oral Cancer Prediction Longitudinal Study (LOH validation), Erlotinib Prevention of Oral Cancer (EPOC) trial, Mallery freeze-dried black raspberry trial, and emerging protocols such as the SAVER (Sodium Valproate for Epithelial Dysplasia) trial. Key challenges addressed include the dysplasia paradox (wherein histology is a poor independent predictor of progression), the surrogate endpoint paradox (wherein biomarker improvement does not guarantee clinical benefit), intratumor heterogeneity, field cancerization, and technical standardization of WES for clinical-grade implementation. We provide a practical framework for integrating WES data with endpoints, discuss FDA biomarker qualification pathways, and outline future directions including multi-omic integration, liquid biopsy-based monitoring, and artificial intelligence-driven discovery of progression biomarkers. Keywords: whole-exome sequencing, chemoprevention, dysplasia, biomarkers, loss of heterozygosity, composite endpoints, causal inference, oral cancer prevention