LOSS OF HETEROZYGOSITY OF APC AND MCC GENES IN ORAL SQUAMOUS-CELL CARCINOMAS IN TAIWAN

Loss of heterozygosity (LOH) at adenomatous polyposis coli (APC) and m utated in colon cancer (MCC) genes was investigated in 37 untreated hu man primary oral squamous cell carcinomas (SCCs) using the polymerase chain reaction. LOH was observed in 14 of 26 (53.8%) heterozygous (inf ormative) patients at APC and 9 of 13 (69.2%) heterozygous patients at MCC. Homozygous deletion of MCC was detected in one patient. Of the 3 7 patients, 29 were informative at APC or MCC or both; LOH at APC and/ or MCC was detected In 68.9% (20/29) of the cases. Ten cases were info rmative for both genes LOH at both loci was found in only three of the se cases. LOH at the APC and/or MCC was found in both early and advanc ed stages of oral SCCs. No significant correlation was observed betwee n LOH at the APC and/or MCC locus and the patients' tobacco/betel quid consumption, tumour location, TNM status, or histological differentia tion. These results suggest that LOH at the APC and/or MCC may be an e arly event and may play a role in the pathogenesis of human oral SCCs in Taiwan.