Moreoever, it has been reported that diffuse gastric-type adenocarcinoma, which cytologically and immunohistochemically resembles invasive lobular carcinoma in that it is composed of discohesive signet-ring cells that lack E-cadherin protein expression, demonstrates down regulation of claudin 4 protein [40,41]. This evidence concerns the gene CDH1 and invasive lobular breast carcinoma.