Expression levels of microRNA-145 and microRNA-10b are associated with metastasis in non-small cell lung cancer

Although metastasis remains the overwhelming cause of death for patients with non-small cell lung cancer (NSCLC), the underlying mechanisms of metastasis remain unknown. Accumulating evidence suggests that microRNAs (miRNAs) are key players in the regulation of tumor cell invasion and metastasis. Expression of miR-9, miR-10b, miR-145, and miR-155, 4 miRNAs previously shown to play roles in metastasis in other tumor types, was compared in lymph node (LN)-positive NSCLC versus LN-negative NSCLC. Expression of miR-145 was significantly lower in LN-positive NSCLC (P < 0.05), while expression of miR-10b was significantly higher (P < 0.05). Expression of both miR-145 and miR-10b was correlated with lymph node metastasis in NSCLC (both Ps < 0.001). In addition, miR-10b facilitated the migration and invasion of lung cancer cell line A549, while miR-145 suppressed the migration and invasion capacity of A549 in vitro. These results suggest that miR-10b and miR-145 may act as an oncogene or tumor suppressor gene, respectively, in NSCLC metastasis.