Chromosome 22q a frequent site of allele loss in head and neck carcinoma

Background. Loss of heterozygosity (LOH) correlates with inactivated tumor suppressor genes. LOH at chromosome arm 22q has been found in a variety of human neoplasms, suggesting that this region contains a tumor suppressor ge ne(s) other than NF2 important to tumorigenesis. The aim of this study was to evaluate the presence of LOH on chromosome 22q11.2-13 and determine whet her there was a relationship between loss in this genomic region and tumor histologic parameters, anatomic site, and survival in patients with squamou s cell carcinoma of the head and neck (HNSCC). Methods. Fifty matched blood and HNSCC tumor samples taken at the time of s urgical treatment were evaluated for LOH by use of four microsatellite mark ers mapping to 22q11.2-q13. Clinical information was available for all pati ents. The frequency and distribution of LOH was correlated with clinical (a ge, sex, use of tobacco and alcohol, site of primary tumor, clinical stage, adjuvant therapy and overall survival) and histologic parameters (histopat hologic stage, tumor differentiation). Results. LOH at 22q was found in 19 of 50 (38%) informative tumors. The res pective incidence of allelic loss for the patients was as follows: 28% at D 22S421, 10% at D22S277, 8% at D22S44S, and 4% at D22S280. No statistical di fferences were apparent with a mean follow-up of 30 months. Laryngeal tumor s showed a higher incidence of LOH compared with oral tumors. Conclusions. These results suggest that the D22S277 locus may be closely li nked to a tumor suppressor gene (TSG) and involved in upper aerodigestive t ract carcinogenesis. In particular, laryngeal tumors may harbor another put ative TSG on 22q11.2-q12.3 that may play a role in aggressive stage III/IV disease. (C) 2000 John Wiley & Sons, Inc.