Positive expression of chemokine (C-C Motif) ligand 18 and prognosis in cancer: A meta-analysis.

Purpose: Chemokine (C-C Motif) Ligand 18 (CCL18) is a chemotactic cytokine involved in the pathogenesis and progression of various cancers by activating downstream signaling pathways and affecting cellular behaviors. We conducted a meta-analysis to evaluate the CCL18 as a prognostic marker for cancer and determine the relationship between CCL18 and clinicopathological features of cancer. Methods: We searched the PubMed, Cochrane, Embase, Web of Science and SinoMed databases for publications to investigate the association between CCL18 expression and survival outcome in cancer. Hazard ratios (HRs) and 95% confidence intervals (CI) of overall survival (OS) were pooled. Odds ratios (ORs) of clinicopathological features were computed. Meta-analysis was performed using STATA 12.0 software. Results: Our meta-analysis identified a total of 17 studies including 2829 cases. Meta-analysis revealed that the expression of CCL18 in various cancer tissues was significantly higher than that in the normal group (OR=16.694, 95% CI=14.117-27.476, p<0.01, random effects). The abnormal expression of CCL18 was associated with lymph node metastasis (OR=4.409, 95% CI=2.129-9.128, p<0.01, random effects) and TNM stage (breast cancer subgroup: III+IV vs I+II OR=13.187, 95% CI=8.417-20.660, p<0.01; gastric cancer subgroup: III+IV vs I+II OR=0.034, 95% CI=0.008-0.137, p<0.01) but is was not related to gender (male vs. female: OR=0.88, 95% CI=0.667-1.162, p=0.368) and age (> 60 vs. =60 years: OR=1.118, 95% CI=0.795-1.571, p=0.522). CCL18 overexpression was associated with poor overall prognosis of breast cancer (Hazard Ratio/HR=2.969, 95% CI=1.361-6.478, p<0.01, random effects). Conclusions: CCL18 is highly expressed in cancer tissues and is closely related to tumor metastasis and prognosis, and its role in tumor development is worth of further study.