Clinicopathological And Prognostic Significance Of Tumor-associated Macrophages Infiltration In Gastric Cancer And Their Correlation

OBJECTIVE:Tumor-associated macrophages(TAMs)can be divided into M1 and M2 phenotypes,which may exert opposite effects on the prognoses of patients with gastric cancer(GC).This meta-analysis was conducted to investigate the clinicopathological and prognostic significance of tumor-associated macrophages infiltration in GC.METHODs:We searched PubMed,Embase and the Cochrane Library for full-text literatures according to eligibility criteria.We decided to use the odds ratio(OR)and hazard ratio(HR)as the appropriate parameters for evaluation of clinicopathological and prognostic significance of TAMs,respectively.Heterogeneity was assessed by Q-test and I~2-statistic.Sensitivity analysis was performed to investigate the stability of results.Potential publication bias was explored by Begg's tests and Egger's tests.RESULTs:1,388 GC patients from 12 studies were included.The pooled outcomes showed that high total TAMs infiltration was significantly correlated with female(OR=1.43,95%CI=1.03–1.98;P=0.033;I~2=0.0%,P=0.826),Borrmann type III/IV(OR=2.09,95%CI=1.30–3.36;P=0.002;I~2=0.0%,P=0.993),lower differentiation degree(OR=1.82,95%CI=1.18–2.82;P=0.007;I~2=24.4%,P=0.250),metastasis(OR=3.38,95%CI=1.68–6.80;P=0.001;I~2=0.0%,P=0.804)and TNM stage III/IV(OR=2.37,95%CI=1.63–3.44;P<0.001;I~2=0.0%,P=0.466).Our results also implied that high total TAMs infiltration levels corresponded to worse overall survival(OS)in patients with GC(HR=1.70,95%CI=1.39–2.09;P<0.001),and a similar result was observed in relation to M2 macrophages infiltration(HR=1.71,95%CI=1.19–2.45;P=0.004).In contrast,elevated M1 macrophages density in GC patients was associated with longer OS(HR=0.46,95%CI=0.33–0.65;P<0.001).CONCLUSION:Overexpression of TAMs is associated with female,Borrmann type III/IV,lower differentiation degree,metastasis and TNM stage III/IV.Moreover,numbers of the total TAMs and M2 macrophages infiltration might be negative prognostic factors for patients with GC,while M1 macrophages infiltration may be associated with a favorable survival rate.