Molecular pathology of head and neck cancer

D.L. Crowe1, J.G. Hacia2,3, C.-L. Hsieh3,4, U.K. Sinha5 and D.H. Rice5

1Center for Craniofacial Molecular Biology, 2Institute for Genetic Medicine,
3Department of Biochemistry and Molecular Biology, 4Department of Urology and
5Department of Otolaryngology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA

Offprint requests to: David L. Crowe, Associate Professor, University of Southern California, 2250 Alcazar Street, Los Angeles, CA 90033, USA. Fax: 323-442-2981. e-mail: dcrowe@hsc.usc.edu

 

Summary. Squamous cell carcinoma of the head and neck region (HNSCC) is the sixth most frequent cancer worldwide, comprising almost 50% of all malignancies in some developing nations. In the United States, 30,000 new cases and 8,000 deaths are reported each year. Survival rates vary depending on tobacco and alcohol consumption, age, gender, ethnic background, and geographic area. This variability reflects the multifactorial pathogenesis of the disease. Early detection and diagnosis has increased survival but the overall 5 year rate of 50% is among the lowest of the major cancers. Differences between normal epithelium and cancer cells of the upper aerodigestive tract arise from specific alterations in genes controlling DNA repair, proliferation, immortalization, apoptosis, invasion, and angiogenesis. These proteins include both tumor suppressors and activating oncogenes which regulate a wide variety of intracellular signaling pathways. Included in these pathways are growth factor receptors, signal transducers, and transcription factors which regulate DNA damage response, cell cycle arrest, and programmed cell death. In head and neck cancer, alterations of three signaling pathways occur with sufficient frequency and produce such dramatic phenotypic changes as to be considered the critical transforming events of the disease. These changes include mutation of the p53 tumor suppressor, inactivation of the cyclin dependent kinase inhibitor p16, and overexpression of epidermal growth factor receptor (EGFR). This review will focus on the molecular changes which occur in these pathways and how they contribute to the pathogenesis of HNSCC. Histol. Histopathol. 17, 909-914 (2002)

Key words: p53, Epidermal growth factor receptor, p16, Cell cycle, Tumor supresor

DOI: 10.14670/HH-17.909