Prognostic Implications of miR-302a/b/c/d in Human Gastric Cancer

Background: The microRNA (miR)-302 family consisting four members, miR-302a, miR-302b, miR-302c and miR-302d, plays an important role in diverse biological processes, and regulates many pathological changes, including cancer. However, the involvement of the miR-302 family into human gastric cancer (GC) remains unclear. The aim of this study was to investigate the expression patterns of miR-302a/b/c/d and determine their clinical significance in GC. Materials and methods: Expression levels of miR-302a/b/c/d in 160 pairs of human GC and matched normal mucosa tissues were detected by quantitative real-time polymerase chain reaction. Then, the associations of miR-302a/b/c/d expression with various clinicopathological characteristics and patients’ prognosis were statistically evaluated. Results: The expression levels of miR-302a, miR-302b and miR-302c in GC tissues were all significantly lower than those in matched normal mucosa (all P < 0.001), but miR-302d expression had no significant differences between cancer and normal groups. Additionally, GC patients with low miR-302a, miR-302b and miR-302c expression more frequently had positive lymph node metastasis (all P < 0.05), advanced TNM stage (all P < 0.05) and great depth of invasion (all P < 0.05). More importantly, low miR-302a, miR-302b and miR-302c expression in GC tissues were significantly associated with shorter disease-free and overall survivals of GC patients (all P < 0.05). Further multivariate analysis identified miR-302a, miR-302b and miR-302c as independent prognostic markers for GC patients. Conclusions: GC patients with the decreased expression of miR-302a, miR-302b and miR-302c may had aggressive cancer progression and unfavorable prognosis. Further rigorous validation based on a large cohort of clinical cases should be performed.