BIOANALYTICAL BIOMARKERS IN ORAL CANCER DETECTION AND THERAPEUTIC MONITORING

Abstract

Oral cancer remains a significant clinical problem, and prognosis is heavily dependent on the stage at diagnosis and the capacity to track the evolution of the disease during and after treatment. Bioanalytical biomarkers can provide additional information to traditional examination and histopathology and provide contemporisation of molecular alterations occurring during the process of carcinogenesis, tumor behavior, treatment response, residual disease, and recurrence. This review synthesizes current evidence on genomic, epigenomic, transcriptomic, proteomic, metabolomic, inflammatory, immune, and circulating biomarkers relevant to oral cancer. This also explores the diagnostic uses of saliva, blood, tissue, cytological and emerging matrices and analytical platforms such as PCR-based assays, sequencing, immunoassays, mass spectrometry, biosensors, microfluidics and lab-on-a-chip systems. A special focus is given to the use of longitudinal applications, like therapeutic-response assessment, minimal residual disease detection, recurrence surveillance, and personalized monitoring. Other novel methods such as multi-omics integration, spatial profiling, extracellular-vesicle analysis, nanotechnology and artificial intelligence are also reviewed for their translation potential. Even with the advancement of technology, there are still challenges to its routine clinical use due to tumor heterogeneity, preanalytical variability, limited assay standardization, limited external validation, and regulatory challenges. Further advances will rely upon prospective multicenter studies, harmonized workflows and clinically interpretable multimarker models that will help in earlier diagnosis and more accurate therapeutic monitoring.