MAP2K1 and esophageal squamous cell carcinoma: In particular, miR-181a-5p inhibits cell migration, invasion and proliferation by repressing the ERK-matrix metalloprotease (MMP) pathway via targeting the Dual specificity mitogen-activated protein kinase kinase 1 (MAP2K1/MEK1) as shown in esophageal squamous cell carcinoma [11].