Increased invasive ability (Figure 5G andFigure S7D) and p-ERK1/2 expression (Figure 5H andFigure S7E-F) were observed in ESCC cells with forced expression of MDK. Knockdown of MDK by using siMDK #3, which targeted the 3'UTR of MDK, reduced p-ERK1/2 and p-AKT expression (Figure 5H). Here, MAPK3 is linked to esophageal squamous cell carcinoma.