Upregulation of microRNA-23a/b promotes tumor progression and confers poor prognosis in patients with gastric cancer.

BACKGROUND AND PURPOSE To investigate the clinical significance of microRNA (miR)-23a and miR-23b expression in human gastric cancer (GC). METHODS Quantitative RT-PCR was performed to detect the expression changes of miR-23a and miR-23b in 160 human GC tissues and paired normal mucosa. The associations between miR-23a and miR-23b expression, and the selected clinicopathological characteristics and patients' prognosis were also evaluated. RESULTS MiR-23a (GC vs. Normal: 3.98 ± 1.23 vs. 2.29 ± 1.12, P < 0.001) and miR-23b (GC vs. Normal: 3.70 ± 1.24 vs. 1.58 ± 1.18, P < 0.001) expression were both increased dramatically when compared with paired normal mucosa. Notably, the expression levels of miR-23a in GC tissues were positively correlated with those of miR-23b (Spearman correlation coefficient r = 0.77, P < 0.001). Then, the coexpression of miR-23a and miR-23b (miR-23a-high/miR-23b-high) in GC tissues was significantly associated with the advanced TNM stage (P < 0.001), the presence of lymph node metastasis (P = 0.008) and the great depth of invasion (P = 0.02). Furthermore, both univariate and multivariate analyses showed that miR-23a/miR-23b co-expression was an independent predictor for unfavorable overall survival. CONCLUSIONS These results suggest that the dysregulation of miR-23a and miR-23b may be implicated in the progression of human GC. Combined expression of miR-23a and miR-23b appears to be a valuable marker for prognosis of this disease.