As a result, heterogeneity was observed in subgroup analysis of types of MMPs, HR statistics, and sources of MMPs, in which heterogeneity was provided by MMP-9 (P heterogeneity = 0.028, I2 = 51.7%), reported HR (P heterogeneity = 0.01, I2 = 52.0%), tumor source (P heterogeneity = 0.024, I2 = 45.7%) and tumor diameter cutoff value (2-5cm: P heterogeneity = 0.020, I2 = 62.5%). Here, MMP9 is linked to neoplasm.