Biologic markers, cellular differentiation, and metastatic head and neck cancer

The plateau in survival rates from head and neck cancer as well as the increasing incidence of disease among various populations demands the need for new perspectives in head and neck oncology. In pursuit of that goal, investigators have been developing improved biologic markers for metastatic risk of head and neck cancer. Such markers can be placed into categorical groupings, of which markers for cellular differentiation may be the most relevant. Among the growth factors relevant to head and neck cancer, epidermal growth factor and its receptor have received the most attention. Those tumors with unregulated growth factor control tend towards a more dedifferentiated state. Additionally, the degree of cellular differentiation and resulting risk of metastases may be predetermined in an individual through constitutively expressed susceptibility genes. Polymorphisms of the L-myc oncogene identified within peripheral blood lymphocytes may represent such a marker. Certain polymorphisms of this gene will identify individuals likely to express dedifferentiated head and neck cancer. Finally, the expression of cell-surface differentiation antigens may govern the capacity of cell-mediated host immune systems to control metastatic growth.