Integration of biomarkers including molecular targeted therapies in head and neck cancer.

Head and neck tumors comprise a wide spectrum of heterogeneous neoplasms for which biomarkers are needed to aid in earlier diagnosis, risk assessment and therapy response. The search for biomarkers includes evaluation of tumor tissues and surrogate materials by molecular, genomic and phenotypic means. Ideal biomarkers should be accurate and easy to perform, highly specific, objective, quantitative, and cost effective. Because of the heterogeneity of head and neck tumors, the integration of multiple selected markers in association with the histopathologic features is advocated for risk assessment. For targeted therapy, however, a single key molecule must be identified. Key molecules and pathways for targeted therapy include growth factor receptors, MAPk/ERk pathway, angiogenesis, and epithelial to mesenchymal transition. Over-expression and mutations of genes in these pathways including EGFR, VEGF, HER2, BRAF and RET, contribute to tumorigenesis in head and neck cancers from squamous carcinomas, to salivary adenocarcinomas and thyroid carcinomas, both follicular and c-cell derived. Monoclonal antibodies to the EGFR receptor and oral tyrosine kinase inhibitors are currently being studied in multiple phase II and III clinical trials to determine their efficacy in head and neck cancers and correlative studies for biomarkers are on-going.