In an inverse manner, qPCR analysis showed that Hk2 mRNA levels were significantly up-regulated in these same ZD tissues (up 5.8-fold in hyperplastic ZD vs ZS esophagus & up 5.4-fold in archived samples [28] of ESCC-bearing ZD esophagus vs non-ESCC-bearing ZS esophagus (P < 0.01 to P < 0.001, n = 8 rats/group) (Figure 3B). Here, HK2 is linked to esophageal squamous cell carcinoma.