Mucin Expression in Colorectal Cancer (CRC): Systematic Review and Meta-Analysis

Background:A body of evidence has suggested that mucins play an important role in adhesion, invasion, and cancer metastasis. However, this evidence is scarce and sometimes confusing.Objective:We performed a systematic review and meta-analysis of available studies to better define the role of mucins in the behavior of colorectal cancer (CRC).Methods:Medical literature was searched through November 30, 2017, using suitable keywords. Pooled estimates, that is, odd ratios (ORs), were obtained using fixed or random-effects models, as appropriate. Heterogeneity between studies was evaluated with the Cochran Q test and I² values, whereas the likelihood of publication bias was assessed by constructing funnel plots. Their symmetry was estimated by the Begg and Mazumdar adjusted rank correlation test and by the Egger regression test.Results:A total of 2234 CRC patients were included in 12 studies, eligible for meta-analysis. There was a significant difference concerning total mucin expression between CRC patients and controls [pooled ORs (95% confidence interval)=8.156 (2.624-25.354), test for overall effect Z=3.627, P<0.0001]. There was no significant publication bias. This significant difference was constricting to MUC1. In addition, there was a significance concerning MUC1 overexpression according to the stage of CRC, that is advanced stage versus localized disease [ORs (95% confidence interval)=2.724 (1.211-6.127), Z= 2.423, P=0.015], as opposed to MUC2 and MUC4.Conclusions:MUC1 is overexpressed in CRC tissue comparing with healthy mucosa, and may have a role in the neoplastic transformation and metastatic process. MUC2 has probably no role in carcinogenesis.