Expression of miR-93-5p and miR-27a-3p in rectal cancer tissues and its clinical significance

Objective: To investigate the miRNA expression profiles in rectal cancer tissues and their associations with clinical pathological stage, depth of tumor invasion, and lymph node metastasis, and to evaluate the potential of miRNA as diagnostic and prognostic markers of rectal cancer. Methods: Human miRNA microarray was used to profile miRNA expression in rectal cancer tissues and matched adjacent normal tissues (n = 71). The up-regulated miR-93-5p and down-regulated miR-27a-3p were screened out, and the top differentially expressed miRNA were validated by quantitative real-time polymerase chain reaction (qRT-PCR). The relationship between the expression of miRNA and clinical parameters was analyzed by ANOVA and Spearman correlation. Results: The expression of miR-27a-3p was down-regulated in miRNA microarray, but was up-regulated in qRT-PCR analysis; the data were relatively discrete. The expression of miR-93-5p was up-regulated in both miRNA microarray and qRT-PCR analysis; the expression level of miR-93-5p in rectal cancer tissues was 3.165 times that in adjacent normal tissues (P = 0.0058); the expression level was correlated with tumor volume (P = 0.004), and was positively correlated with the level of carcinoembryonic antigen (CEA) before treatment (P =0.001) and the number of lymph nodes metastases (r_s = 0.534, P = 0.005). Conclusions: There is a differential miRNA expression pattern between rectal cancer tissues and matched adjacent normal tissues. The miR-93-5p is highly up-regulated in rectal cancer tissues and may serve as a diagnostic and prognostic marker of rectal cancer. (authors)