FOXM1 and esophageal squamous cell carcinoma: To further verify the expression of FOXM1c at the protein level, we generated a mouse monoclonal antibody (McAb) directly against the exon Va (thus named Va), which is only contained in FOXM1a and FOXM1c.32 Considering that FOXM1a was negligibly expressed in ESCC (Figure 1B) and in pancreatic and colorectal cancers as described previously,14, 33 we argued that this McAb Va mainly recognized FOXM1c at least at the above cancer types.