SLC39A6 and esophageal squamous cell carcinoma: We found that the immunohistochemical cut-off scores of SLC39A6 easily distinguished the ESCC, HGIN, and LGIN tissues from the normal esophageal tissues, all of which demonstrated high sensitivity and specificity values according to the area under ROC curve (all >0.7, Fig. 3; Additional file 4: Table S3).