Objective To detect the differentially expressed genes in oral lichen planus（OLP） by cDNA microarray. Methods The PCR products of 4 000 genes were spotted on chemical material coated glass plates in array. The total RNAs were isolated from OLP and normal oral mucosa tissue and were purified to mRNA. Both the mRNA were reversely transcribed to cDNA with the incorporations of fluorescent dUTP, for preparing the hybridization probes. The mixed probes were then hybridized to the cDNA microarray. Microarray was scanned for the fluorescent signals and showed the differences between the two samples. Results The expressions of 122 genes were up regulated while the expressions of 91 genes were down regulated in OLP among the 4 000 target genes. The up- regulated genes were mainly the ones of immunity related genes, metabolize related genes, oncogene, cytokine and cell signal transduction protein. The down- regulated genes were mainly the ones of DNA binding and transcription factors, cell signal transduction protein, immunity related genes, metabolize related genes, and cytokine. Conclusion Two hundred and thirteen differentially expressed genes with different functions were revealed in OLP, which may play some roles in the progression of OLP.
