Genetic aberrations in oral or head and neck squamous cell carcinoma (SCCHN): 1. Carcinogen metabolism, DNA repair and cell cycle control

Thr ability to metabolise carcinogens or pro-carcinogens. repair DNA damage , and control cell signalling and the cell cycle are fundamental to homeost asis. Oral squamous cell carcinoma (oral cancer) and many squamous cell car cinomas of the head and neck (SCCHN) may, under appropriate exposure to mut agens, arise if these mechanisms are defective. SCCHN arise as a consequenc e of multiple molecular events induced by the effects of various carcinogen s from habits such as tobacco use, influenced by environmental factors, pos sibly viruses in some instances, against a background of heritable resistan ce or susceptibility. Consequent genetic damage affects many chromosomes an d genes, and it is the accumulation of these changes that appears to lead t o carcinoma in some instances, sometimes via a clinically evident pre-malig nant, or potentially malignant, lesion. Although lifestyle factors play a p rominent role in aetiology, some patients appear susceptible because of an inherited trait in their ability or inability to metabolise carcinogens or pro-carcinogens, possibly along with an impaired ability to repair the DNA damage. This is the first of a series of three papers reviewing the advance s in the understanding of this urea of research since our last review [Scul ly C, Field JK. Genetic aberrations in squamous cell carcinoma of the head and neck (SCCHN), with reference to oral carcinoma (Review). Int J Oncol 19 77;10:5 21] and discusses mainly oral carcinoma in the context of SCCHN (C) 2000 Elsevier Science Ltd. All rights reserved.