将乳腺肿瘤分类为导管或小叶是一项日常工作，依赖于组织学和免疫组织化学工具的结合。历史上，E-钙粘蛋白分子的缺失与小叶肿瘤之间存在密切的联系，这使得通过免疫组织化学对E-钙粘蛋白进行染色成为该诊断过程的主要内容。不幸的是，E-钙粘蛋白表达和组织形态学之间的不一致，以及E-钙粘蛋白染色模式和强度的变化在临床实践中比比皆是，但往往被忽视，倾向于对E-钙粘蛋白结果的二元解释。在本文中，我们通过回顾 E-钙粘蛋白及其相关基因 (CDH1) 来强调 E-钙粘蛋白表达的复杂性、导致 E-钙粘蛋白表达异常/缺失的机制，以及这些因素对 E-钙粘蛋白表达的影响。 E-钙粘蛋白免疫组织化学染色在乳腺导管肿瘤与小叶性乳腺肿瘤分类中的可靠性。© 2024 作者。组织病理学由约翰·威利出版

Categorizing breast neoplasia as ductal or lobular is a daily exercise that relies on a combination of histologic and immunohistochemical tools. The historically robust link between loss of the E-cadherin molecule and lobular neoplasia has rendered staining for E-cadherin by immunohistochemistry a staple of this diagnostic process. Unfortunately, discordances between E-cadherin expression and histomorphology, and variations in E-cadherin staining patterns and intensities abound in clinical practice, but are often neglected in favour of a binary interpretation of the E-cadherin result. In this article, we highlight the complexities of E-cadherin expression through a review of the E-cadherin protein and its associated gene (CDH1), the mechanisms leading to aberrant/absent E-cadherin expression, and the implications of these factors on the reliability of the E-cadherin immunohistochemical stain in the classification of ductal versus lobular mammary neoplasia.© 2024 The Author(s). Histopathology published by John Wiley & Sons Ltd.