The presence of TP53 mutations in dysplastic samples but not non-dysplastic samples, and the absence of SMAD4 mutations in BE samples agrees with the work of Weaver et al., who proposed that mutation of TP53 marked the boundary from non-dysplastic to dysplastic and that SMAD4 mutations are only present in invasive cancer [14]. This evidence concerns the gene TP53 and Barrett esophagus.