Microsatellite Alterations at Chromosome 9p in Hyperplasia, Dysplasia, and Oral Squamous Cell Carcinoma

Objective: To better understand genetic abnormalities in hyperplasia and oral squamous cell carcinoma (OSCC), Method: we examined 30 samples from patients with hyperplasia, 28 samples from patients with dysplasia and 22 samples from patients with OSCC. The samples were analyzed by polymerase chain reaction (PCR) for four microsatellite markers D9S171, D9S161, D9S162 and D9S157 located at chromosomes 9p. The percentage of loss of heterozygosity (LOH) and microsatellite instability (MSI) was assessed with Crosstabs statistics. Result: LOH and MSI in at least one locus was identified in 20% (6/30) patients with hyperplasia, 46% (13/28) patients with dysplasia and 77% (17/22) patients with OSCC. Crosstabs statistic outcome showed that there were significant differences between hyperplasia group and dysplasia group (P=0.032), dysplasia group and OSCC group (P=0.027), hyperplasia group and OSCC group (P<0.001). Conclusion: Our data suggest that microsatellite alterations have already occurred in hyperplasia, dysplasia and OSCC. The positive rate of LOH and MSI in the 9p was increased significantly according to progression of cancerization of oral epithelium. This may be involved in early processes of carcinogenesis in OSCC. The microsatellite alteration in premalignant tissues may serve as markers for cancer risk assessment.