Molecular pathology of head-and-neck cancer.

Each year approximately 40,000 people in the United States and 500,000 people worldwide are diagnosed with head-and-neck squamous cell carcinoma (HNSC). Although there have been significant improvements in the treatment of this disease, leading to decreased morbidity, over the past few decades the 5-year survival rate has remained largely unchanged at 50%. Genetic and epigenetic alterations as well as viral agents have been implicated in the development of head-and-neck cancer. Advances in our understanding of the molecular biology underlying these processes have spawned numerous, diverse strategies to exploit this understanding in applied pathology. Preliminary investigations have analyzed body fluids and margins for the presence of cancer cells. Specific molecular alterations have been associated with improved treatment response and prognosis. Molecular therapy has been shown to have some clinical efficacy in HNSC. Expression profiles may be generated for specific primary tumors and compared to known markers of disease. Improved molecular characterization of primary tumors, surgical margins and body fluids may allow clinicians to detect and treat earlier lesions, predict a tumor's response to treatment, tailor treatment to specific molecular alterations and ultimately improve clinical outcomes related to HNSC.