This is especially true in Barrett metaplasia, since the junctional and fundus-type metaplasias, in which NIS is normally expressed, pose a much lower risk of malignant transformation than intestinal metaplasia, which exhibits no NIS expression and gives rise to a higher number of dysplastic alterations and adenocarcinomas even in small (i.e., <3-cm) lesions[34]. Here, SLC5A5 is linked to Barrett esophagus.