Chromosomal alterations in squamous cell carcinomas of the head and neck: Window to the biology of disease

Background. Cytogenetic alterations underlie the development of squamous ce ll carcinomas of the head and neck (SCCHN), Because many of the molecular g enetic changes in SCCHN result from chromosomal alterations, a complete per spective on the genetic changes in tumors requires a basic introduction to cytogenetics. This review presents a brief description of the latest cytoge netic techniques and a description of chromosomal alterations in SCCHN, the ir molecular correlates. and clinical implications. Results. The most frequent cytogenetic alterations in SCCHN are gains of 3q , 8q, 9q, 20q, 7p, 11q13, and 5p and losses of 3p, 9p, 21q, 5q, 13q, 18q, a nd 8p. The karyotypes often provide an explanation for the mechanism by whi ch the molecular genetic alterations arose. For example, the coordinate gai ns and losses involving whole arms of chromosomes 3, 5, 7, 8, and 9 often r esult from isochromosome formation. In addition, apparent allelic imbalance s may not represent loss of heterozygosity but gene amplification. These re sults suggest that cytogenetic analysis is valuable for placing the molecul ar genetic findings in perspective at the cellular level. Conclusions. Cytogenetic endpoints may be useful tools for dissecting clini cal differences in tumor behavior and response to therapy. Numerous studies are underway to examine the biology of and genetic alterations in SCCHN th at will lead to additional markers for use as rapid, noninvasive screening methods for individuals at high risk for primary or recurrent SCCHN. Our go al is to minimize morbidity and mortality from SCCHN by identifying useful predictors of disease and recurrence risk and response to therapy to implem ent earlier detection and more effective prevention and/or treatment strate gies. (C) 2001 John Wiley & Sons, Inc.