CDH1 and signet ring cell carcinoma: Although this is the first report of nuclear E-cadherin in human lung cancer, aberrant staining of E-cadherin in the nucleus has been reported in other types of cancer including Merkel cell carcinoma, signet ring cell carcinoma and solid pseudopapillary tumors of the pancreas.31, 32, 33 Furthermore, those cancers with nuclear E-cadherin also show increased β-catenin levels in the nucleus.31, 32, 33 It is unclear whether an aberrant nuclear localization of E-cadherin has an anti- or pro-oncogenic role, for example, via modulating β-catenin-mediated signaling.