JUN and esophageal squamous cell carcinoma: In normal epithelium, c-Jun correlated with cystatin A (P<0.001), involucrin (P = 0.003) or SPRR3 (P<0.001), and in ESCC, c-Jun significantly correlated with cystatin A (P<0.001), involucrin (P = 0.021) and SPRR3 (P = 0.019) as well.