An allelotype of squamous carcinoma of the head and neck
Tumour suppressor gene (TSG) inactivation plays a major role in the development of cancer. To date there has been no reported systematic approach to the identification of such genes in the development of squamous carcinoma of the head and neck (SCCHN). We have therefore analysed allelic loss of heterozygosity (LOH) in a series of 28 patients with a primary SCCHN. Using the polymerase chain reaction (PCR) to amplify Microsatellite markers we have been able to compare allelic loss between normal and tumour DNA. Additional RNase protection assays were used to screen for APC gene mutations while southern blot analysis was performed to identify cyclin-D gene amplification. Our results demonstrate several regions showing a high frequency of LOH: 3p(44%), 5q(43%), 9q(35%), 11q(45%) and 17p(40%). Further analysis of chromosome 5 has highlighted 5q21 (APC/MCC genes) as its commonest site of LOH. However screening the APC gene failed to detect mutations in the mutation cluster region (MCR). Out of 9 tumours with LOH at 11q13 we were able to exclude, by southern blot analysis, cyclin-D amplification in all but one of these tumours. Our results indicate the locations of several possible TSGs involved in the development of SCCHN.