Current Concepts and New Insights from Mouse Models of Mammary Tumors on Epithelial Mesenchymal Transition and its Synergy with Mutant p53
Pages 191-206
A. Piersigilli, A. D. Borowsky, Q. Chen, N.E. Hubbard and R.D. Cardiff
DOI: http://dx.doi.org/10.6000/1927-7229.2015.04.04.8
Published: 18 December 2015

Abstract: Epithelial Mesenchymal Transition (EMT) is the transdifferentiation of epithelial cells into a mesenchymal phenotype. This process occurs during embryogenesis but also in wound healing and in tumors. The neoplastic EMT is characterized by variably complete shedding of epithelial architectural features and acquisition of mesenchymal traits. In immunohistochemistry a variable coexpression of cytokeratins, vimentin or alpha-smooth muscle actin with loss of E-cadherin and other interepithelial adhesion molecules is characteristic. Such transition is associated with mutations both at the genetic (somatic) and epigenetic levels and is believed to confer a more advantageous phenotype for local and distant spread of cancer cells. Mammary carcinoma can exhibit EMT features in humans and mice and it tends to occur more frequently in women with tumors bearing a worse prognosis such as the claudin low subtype within the triple negative cancer. Missense mutation of TP53 is one of the most common mutations in cancer and it is frequently found in EMT tumor types, often with a more aggressive behavior. The current literature and survey of our mouse EMT cases in the Genomic Pathology Center image archives demonstrate a synergy between p53 and EMT that is independent of the initiating oncogene. However, p53 mutation is not sufficient or causal for EMT. Moreover, despite the local malignant behavior, processes such as spontaneous metastases and Mesenchymal Epithelial Transition (MET) appear not to be as frequent and obvious as previously hypothesized.