SLC39A6 and esophageal squamous cell carcinoma: During the multi-stage development of ESCC in the Chinese Han population, IHC analysis showed that the frequency of SLC39A6 protein overexpression was lowest in normal samples (14.39 %) and increased gradually during the evolution of esophageal carcinogenesis, with 51.85 % (42/81) of LGIN and 76.47 % (39/52) of HGIN, and a slight decrease at 66.90 % (95/142) of ESCC but still showing high SLC39A6 protein expression.