Table 3.

Summary of clinical studies defining the role of miR-218 in lung cancer

Study design	Patient characteristics/sample size	miR-218 expression levels	Findings	References
To study the expression of the host genes SLIT2 and SLIT3, and miR-218 in NSCLC patient samples	Samples were collected from 39 lung cancer patients	miR-218 expression was downregulated by 4-fold in NSCLC samples	SLIT2/3 and mir-218 expressions were significantly downregulated in NSCLC samples. Furthermore, smokers (current and former) had significantly decreased levels of miR-218 expression	[58]
To determine the association of PXN with miR-218 expression	Samples were collected from 124 patients with primary lung cancer	miR-218 levels decreased as lung cancer progressed through its stages	PXN expression was significantly elevated and miR-218 expression was downregulated in tumor samples relative to normal tissues	[74]
To determine whether EGFR expression is associated with miR-218 expression	Samples were collected from six lung cancer patients	miR-218 expression was nearly 2-fold higher in normal lung samples compared to NSCLC tissues	EGFR mRNA and protein levels were consistently higher in tumor samples, relative to normal tissues; miR-218 expression was downregulated	[73]
To determine the association of Slug/ZEB2 with miR-218 expression	Samples were collected from 60 NSCLC patients	miR-218 levels were downregulated in NSCLC and declined significantly with advancing TNM stages	Slug/ZEB2 expression was markedly elevated and miR-218 expression was downregulated in tumor samples relative to normal tissues	[83]
To determine the association of TRIM9 with miR-218 expression	Samples were collected from 50 NSCLC patients who did not receive any prior treatments	miR-218 expression was downregulated by 2-fold in NSCLC samples	TRIM9 expression was markedly higher and miR-218 expression was downregulated in tumor samples relative to normal tissues	[80]
To determine whether miR-218 synergistically enhances the efficacy of radiotherapy	Samples were collected from 42 patients with NSCLC who received radiotherapy	miR-218 levels were nearly 2-fold higher in the serum of control patients compared to lung carcinoma patients	miR-218 level in the serum of LC patients after radiotherapy was evidently higher than pre-radiotherapy. PRKDC expression was negatively correlated with miRNA-218–5p levels in the serum of LC patients	[91]

SLIT2/3: Slit guidance ligand 2/3; NSCLC: non-small-cell lung cancer; PXN: paxillin; EGFR: epidermal growth factor receptor; ZEB2: zinc finger E-box-binding homeobox 2; TNM: tumor, node, metastasis; PRKDC: protein kinase, DNA-activated, catalytic subunit; LC: lung cancer.