Decreased miR-198 expression and its prognostic significance in human gastric cancer

Abstract

Background: MicroRNAs (miRNAs) have been proved to play important roles in the tumorigenesis and development of human gastric cancer (GC). Our study aims to investigate the expression and clinical significance of miR-198 in GC patients.

Methods: Quantitative real-time polymerase chain reaction (RT-PCR) was performed to evaluate miR-198 levels in 106 pairs of GC specimens and adjacent noncancerous tissues. Then, the associations of miR-198 expression with clinicopathological factors and patient's survival were determined.

Results: The expression levels of miR-198 in GC tissues were significantly lower than those in corresponding noncancerous tissues (p<0.01). Decreased miR-198 expression was significantly associated with larger tumor size, deeper invasion depth, positive lymph node metastasis, advanced tumor-node-metastasis (TNM) stage, and shorter overall survival. Moreover, multivariate regression analysis identified low miR-198 expression as an independent predictor of poor survival.

Conclusions: These findings suggested that miR-198 downregulation may be associated with progression of GC and that this miR may be an independent prognostic marker for GC patients.

Fig. 1

miR-198 expression was significantly lower in gastric cancer samples than in the corresponding noncancerous tissues (p < 0.01, paired t test). miR-198 expression levels were calculated by the 2^−ΔCT method and normalized to U6 small nuclear RNA

Fig. 2

Kaplan-Meier survival curves of 106 gastric cancer patients based on miR-198 expression status. Patients in the low expression group had significantly poorer prognosis than those the in high expression group (p < 0.001, log-rank test)