The presence of candidate tumor suppressor gene loci at chromosome 3p for oral squamous cell carcinomas.

We investigated the short arm of chromosome 3 (3p) for allelic imbalances, including loss of heterozygosity (LOH) and microsatellite instability (MSI) in 40 primary oral squamous cell carcinomas (SCCs) using 10 microsatellite markers and constructed a deletion map for this chromosome arm. We examined 40 primary tumor tissues, 40 corresponding normal tissues, and seven lymph node metastatic tissues. LOH at one or more loci was found in 24/40 (60%) of tumors. Deletion mapping of these tumors revealed at least three discrete, commonly deleted regions on the chromosome arm. Furthermore, we detected MSI in six of those tested cases (15%). We compared our results with the clinicopathologic features. A number of sites displaying LOH at 3p could be detected in early stage lesions, and the frequencies of LOH tended to be higher in later clinical stages. Thus, the frequent LOH was observed from early stage in pTNM classification. An unknown tumor suppressor gene in the genesis of oral squamous cell carcinoma may exist in 3p.