Microsatellite alterations in squamous cell carcinoma of the head and neck- clustering of loss of heterozygosity in a distinct subset

Loss of heterozygosity (LOH) and microsatellite instability (MSI) have been recognized as important events in the carcinogenesis of many cancers, incl uding squamous cell carcinoma of head and neck (SCCHN). However, microsatel lite alterations have not been documented in SCCHN from Chinese patients. W e investigated the frequency and clinical significance of LOH and MSI in 30 SCCHN from Hong Kong Chinese using polymerase chain reaction on 17 microsa tellite markers on chromosomes 3p, 4q, 7q, 9p, 17p and 18q. LOH was present in nine tumours (30%) and MSI in four (13%). The incidence of LOH (7/13; 5 3.8%) in hypopharyngeal-laryngeal cancers was significantly higher than tha t (2/17; 11.8%)in the oral cancers (P = 0.020). LOH was more often detected at the loci on chromosomes 7 and 9. Patients with tumours having LOW had s lightly poorer outcome compared with those without, although the difference s did not reach statistical significance. Our data show that the incidence of microsatellite alterations in SCCHN from Hong Kong Chinese is low. Howev er, LOH may be one of the genetic mechanisms in the carcinogenesis of a sub set of SCCHN (hypopharyngeal-laryngeal cancers). (C) 2000 Elsevier Science Ltd. All rights reserved.