MELK and esophageal squamous cell carcinoma: To determine MELK expression in human ESCC, we firstly analyzed the transcript expression of MELK in two cohorts of ESCC patients from GEO database, the results showed that the mRNA level of MELK in GSE20347 dataset (32) was much higher in ESCC tissues than that in the corresponding normal tissues (Figure 1A); Similar results were observed in GSE23400 dataset (33), which composes of 53 pairs of ESCC specimens (tumor and matched normal cases) (Figure 1B).