Relationship between micro RNA expression levels and histopathological features of dysplasia in oral leukoplakia.

Background Increased expression of micro RNAs (mi RNAs), mi R-21, mi R-345, and mi R-181b has been demonstrated in oral leukoplakia ( OL) that progresses to oral squamous cell carcinoma ( OSCC), suggesting a mi RNA signature with potential prognostic value. On the basis of these findings, this pilot study aimed to investigate the cytological and histopathological features that are used to grade oral dysplasia and determine associations with the expression of these 3 potentially cancer-related mi RNAs. We also compared the expression levels of these mi RNAs in OL with normal oral mucosa and OSCC. Methods We evaluated mi RNA expression by q PCR in 22 samples of OL demonstrating different grades of dysplasia, as well as 17 cases of OSCC, and 6 samples of normal oral mucosa. We associated the mi RNAs expression profiles with cytological and histopathological features of OL. Results OSCC cases showed increased expression of all 3 mi RNAs when compared with OL and normal oral mucosa. Increased expression of mi R-21 was also observed in OL when compared with normal oral mucosa. We found a higher expression of mi R-21 and mi R-181b in OL that presented with an increased number of mitotic figures, increased nuclear/cytoplasmic ratio, or hyperchromasia. Increased expression of mi R-21 was also detected in OL with abnormally superficial mitosis. Higher expression of miR-345 was observed in OL with an increased number and size of nucleoli or increased nuclear/cytoplasmic ratio. Conclusions In conclusion, the present study shows that some cytological and histopathological parameters used to grade dysplasia are associated with altered mi RNA expression. [ABSTRACT FROM AUTHOR]