Gene expression profiles of oral leukoplakia and carcinoma: genome-wide comparison analysis using oligonucleotide microarray technology.

Although leukoplakia is the most common precancerous lesion of the oral cavity, its molecular biological properties are largely unknown. The aim of this study was to identify the genes responsible for its pathogenesis and malignant transformation using oligonucleotide microarray technology. The expression profiles of 8,800 genes in human oral leukoplakia (n=4) and oral squamous cell carcinoma (OSCC) (n=2) were analyzed using the Affymetrix GeneChip system and the results were confirmed with RT-PCR. Eight genes were up-regulated (>2.0-fold) and ten were down-regulated (<0.5-fold) in all leukoplakias analyzed with the GeneChip. In particular, loricrin and keratins displayed greater differences between normal tissue and leukoplakia. Some of the 18 alternatively expressed genes were markedly down-regulated in squamous cell carcinoma compared with leukoplakia. Our data suggested that gene abnormalities in cytoskeleton network components might be responsible for the development and progression of oral leukoplakia.