Loss of heterozygosity (LOH) on the long arm of chromosome 20 (20q) has been detected in several human cancers. However, little is known about LOH on chromosome 20 in oral squamous cell carcinoma (OSCC). To determine which loci of chromosome 20 were involved in OSCC tumorigenesis, 41 cases of OSCC were examined for LOH state on chromosome 20 at 17 microsatellite loci by PCR-LOH assay. LOH occurred in 41.5% of tumors in at least one locus. Among the 17 loci, D20S48 on 20p11.2 and RPN2 on 20q12-13.1 exhibited higher frequencies of LOH, 27.6% and 31.4%, respectively. The LOH incidence was significantly higher in tumors in which the primary site was on gingiva compared with other oral sites (p=0.012). Our results indicate that allelic deletions on 20q12-13.1 and 20p11.2 may play roles in OSCC carcinogenesis, and suggest that allelic deletions on 20q might have some relation with the primary site of OSCC.
