STAT3 and pachyonychia congenita: ZEB1 is the most critical EMT-associated transcription factor in PC, promoting stemness, invasion, and metastasis of PC.401 Significantly, ZIP4 induces the expression of ZEB1, which mechanically is through phosphorylated STAT3.395 Another report suggested that ZIP4 activates PC migration and invasion by mediating ZEB1 inhibition of ZO-1 and Claudin-1 expression394 (Fig. 6).