BACKGROUND: Non-coding RNA molecules, such as microRNAs, may play an important 
role in carcinogenesis. Recent studies have indicated that microRNAs are 
involved in initiation and progression of various malignancies. However, little 
work has been done to compare the microRNA expression patterns in oral cancer. 
In this study, we constructed an animal model of oral squamous cell carcinoma to 
investigate expression profiles of microRNAs in oral carcinogenesis.
METHODS: The animal model of oral squamous cell carcinoma was conducted by 
tri-weekly (Monday, Wednesday, and Friday) painting with 5% DMBA in acetone. Six 
Syrian hamsters, including three from the treated group and three from the 
control group, were used as a training group for microRNA microarray analysis. 
All microarray data were analyzed by Significance Analysis of Microarrays (SAM) 
and CLUSTER 3.0 software, and this result was further confirmed by qRT-PCR 
assay.
RESULTS: Seventeen microRNAs were differentially expressed in oral squamous cell 
carcinoma. Five microRNAs (hsa-miR-21, hsa-miR-200b, hsa-miR-221, hsa-miR-338, 
and mmu-miR-762) were significantly upregulated and twelve microRNAs 
(hsa-miR-16, hsa-miR-26a, hsa-miR-29a, hsa-miR-124a, hsa-miR-125b, 
mmu-miR-126-5p, hsa-miR-143, hsa-miR-145, hsa-miR-148b, hsa-miR-155, 
hsa-miR-199a, and hsa-miR-203) were down-regulated in cancer tissues. The 
expression levels of hsa-miR-21 and hsa-miR-16 seen with Stem-loop qRT-PCR were 
also seen in microarray analysis in all samples.
CONCLUSION: Our findings identified specific microRNA expression in oral 
squamous cell carcinoma and suggested that microRNAs have a role in oral 
carcinogenesis.