ABSTRACT
Most head and neck malignancies are squamous cell carcinomas originating from the surface epithelium of the head and neck (HNSCC). Histology is usually straightforward. Still, biopsy diagnosis can be difficult either due to inadequate sampling or to tumor characteristics. The most important prognostic factors are T-and N-stage. However, some histologic factors also seem to have prognostic significance, for example extracapsular extension of nodal disease and positive resection margins1
adversely influence prognosis. Other prognostically important histologic features are tumor thickness, especially in the oral cavity2,3, perineural growth, vascular invasion2,4, and the aspect of the invasive margins of the tumor5,6. Tumors invading with pushing borders appear to be less aggressive than tumors growing with a non-cohesive front infiltrating with tiny strands or single cells. Recently an RNA expression profile from primary HNSCC predicting lymph node metastases was reported7. Among the candidate predictor genes, factors were discovered which are known for their essential function in tissue organization (linker/adhesion molecules, matrix proteins). These and other proteins have been studied by immunohistochemistry for their prognostic
importance and will be discussed later in this chapter.
