Abstract 5274: Expression of selected miRNA and miRNA processing genes in oral precancer and cancer tissues.

Abstract

Abstract Introduction: Oral leukoplakia is a premalignant lesion that long has been considered to confer increased risk for the development of Oral Cancer which is highly prevalent in India. Oral lichen planus (OLP) on the other hand is a chronic inflammatory disease whose malignant potential is debatable. Since not all oral precancerous lesions progress to oral cancer, molecular markers like miRNA expression could be used to diagnose and predict progression of disease that cannot be detected histopathologically. Objective: Study of intra- and inter-variation in the expression of a few microRNAs (26a1, 423, 34b, 29a, 193a, 137 and 205) and microRNA processing (XPO5, GEMIN3 and RAN) genes in the three disease types, namely, oral cancer, leukoplakia and lichen planus. Methodology: Total RNA was extracted from paired disease and normal tissues from 15 oral cancer, 19 leukoplakia and 19 OLP patients. Expression of microRNAs and microRNA processing genes were studied using TaqMan assay. Subsequent statistical analyses were performed for interpretation of expression data. Results: Expression of mir 26a-1 and mir 137 genes was dysregulated >2 folds in 70% of the cancer samples while expression of remaining microRNAs and mir-processing genes were deregulated in a few samples. In leukoplakia, expression of mir-26a-1 was dysregulated >2 folds in 50% of the samples while dysregulation in expression of the remaining miRNAs was observed in 1/3rd of the patients. In OLP, there was an interesting trend of unidirectional up or down regulation in the expression of mir26a-1, mir29a, mir-34b and mir-137 genes. We also observed that the average expression of miRNA genes differed among the three patient groups. Conclusion: Deregulation in microRNA expression could not be correlated with individual's tobacco habits. Variation in expression of microRNA as well as miRNA processing genes was observed within individuals of the same patient group (i.e. cancer or leukoplakia or lichen planus) and between any two patients groups. There was correlation in expression of microRNAs which probably explains the unidirectional increase or decrease of miR expression in OLP. Finally, the mean expression level in the three types of disease tissues differed significantly. But expression of more miRNA genes in more samples would be necessary for molecular markers. Citation Format: Bidyut Roy, Roshni Roy, Navonil De Sarkar, Ranjan Rashni Paul. Expression of selected miRNA and miRNA processing genes in oral precancer and cancer tissues. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5274. doi:10.1158/1538-7445.AM2013-5274