Compared with adjacent normal tissues, HK2 was found to be highly expressed in bladder cancer, oesophageal cancer, gastric cancer, head and nest cancer, kidney cancer, lymphoma, ovarian cancer, pancreatic cancer, sarcoma, and brain and central nervous system (CNS)-related cancer (Fig. 1A), suggesting that HK2 may play an important role in tumorigenesis. This evidence concerns the gene HK2 and carcinoma of esophagus.