Ming et al reported that RHCG could suppress the tumorigenicity and metastasis of esophageal squamous cell carcinoma via inhibiting NF-κB signaling and MMP1 expression [15]; Wang et al discovered that RHCG might suppress cervical cancer progression through inducing apoptosis regulated by TGF-β1 [16]. Here, MMP1 is linked to esophageal squamous cell carcinoma.