In summary, the immunofluorescence analysis confirmed that i) PLEKHA7 expression was restricted to the apical region of epithelial gland cells, either facing the lumen in normal ductal carcinomas, or facing the stroma in the inverted polarity micropapillary carcinomas, ii) was distinct from that of either E-cadherin/p120ctn, or cingulin/ZO-1, and iii) was undetectable in lobular carcinomas. This evidence concerns the gene TJP1 and breast ductal adenocarcinoma.