Matrix metalloproteinase-7 mRNA and protein expression in gastric carcinoma: a meta-analysis.

Messenger RNA (mRNA) acts as template for protein synthesis. The matrix metalloproteinase-7 (MMP-7) protein and its mRNA expression have been suggested to be involved in the development of various diseases and cancers. We aimed to study associations between the MMP-7 protein and mRNA expression in gastric carcinoma (GC) patients. We searched in the Science Citation Index, the Cochrane Library, PubMed, Embase, CINAHL, Current Contents Index, and several Chinese databases. Studies were pooled and odds ratios and their corresponding 95 % confidence intervals were calculated. Subgroup analyses and publication bias detection were also conducted. Statistical analysis was performed via Version 12.0 STATA software. An updated meta-analysis based on 16 independent cohort studies was performed to investigate this association. The study suggests that significant differences in MMP-7 protein levels were observed in tumor-node-metastasis (TNM) I-II vs. III-IV (odds radio (OR) =3.19, 95 % confidence interval (95%CI) =1.59 ∼ 6.41, P=0.001), in T1-2 vs. T3-4 invasive grade (OR=1.82, 95%CI=1.07 ∼ 3.12, P=0.028), and in distant metastasis-positive vs. metastasis-negative samples (OR=3.14, 95%CI=1.05 ∼ 9.35, P=0.040). Increased MMP-7 mRNA levels were found to be significantly correlated with invasive grade (T3-4 vs. T1-2: OR=5.61, 95%CI=2.64 ∼ 11.95, P<0.001) and in the lymph node (LN) metastasis (positive vs. negative: OR=7.08, 95%CI=4.20 ∼ 11.93, P<0.001) group. Country subgroup analysis yielded significantly different estimates in the protein expression of MMP-7 of all experimental groups. MMP-7 mRNA levels were increased in LN metastasis-positive GC in contrast to metastasis-negative in China and Korea (all P<0.05); this was not shown in Japan (P>0.05). Higher protein and mRNA levels of MMP-7 were statistically associated with aggressive LN metastasis, advanced TNM stage, and invasion in GC patients; MMP-7 can thus potentially serve as a useful biomarker in determining GC progression and prognosis.