Pathobiology of head and neck squamous tumorigenesis

Head and neck squamous epithelial carcinogenesis is a complex multistep process that entails a progressive acquisition of alterations in diverse vital cellular pathways. The nature of these alterations and the order of their occurrence have remained unresolved. In the past 15 years, the thrust of research in this field has centered on the epithelial genetic and/or epigenetic changes attendant to their development and progression. Little efforts, however, have been expended on changes in structural or host microenvironment and their role in these tumors. Only recently has the latter topic become the focus of attention. This review will address recent advances in both cellular and structural findings in head and neck squamous carcinoma development and progression. Targeting these events for biological and therapeutic approaches is a desirable goal for future effective treatment of patients with this cancer.