Background: The aim of this study was to investigate differences of miRNA-34a expression in benign andmalignant colorectal lesions. Materials and Methods: Samples of cancer, paraneoplastic tissues and polypswere selected and total RNA was extracted by conventional methods for real-time PCR to detect the miRNA-34a expression. In addition, the LOVO colorectal cancer cell line was cultured, treated with the demethylatingagent 5-azacytidine and screened for differentially expressed miRNA-34a. Results: After the drug treatment,the miRNA-34a expression of colorectal cancer cell line LOVO was increased and real-time PCR showed thatlevels of expression in both cell line and colorectal cancer tissues were low, as compared to paraneoplastic tissue(p<0.05). Polyps tissues had significantly higher expression than paraneoplastic and colorectal cancer samples(p<0.05). Conclusions: miRNA-34a-5p may play a role as a tumor suppressor gene in colorectal cancer, withinvolvement of DNA methylation.
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