WIF1 and esophageal cancer: Down-regulation of WIF1 has been reported in prostate, breast, lung, bladder, salivary gland and esophageal cancers [66], [67] and evidence of promoter hypermethylation in Barrett's esophagus cases that progress to esophageal adenocarcinoma suggests that loss of expression likely represents an early event in carcinogenesis [66].