Published online May 16, 2015. doi: 10.12998/wjcc.v3.i5.393
Peer-review started: January 28, 2015
First decision: February 7, 2015
Revised: February 12, 2015
Accepted: March 30, 2015
Article in press: April 2, 2015
Published online: May 16, 2015
Processing time: 101 Days and 19.2 Hours
Epithelial-to-mesenchymal transition (EMT) represents conversion of an epithelial cell in an elongated cell with mesenchymal phenotype, which can occur in physiologic and pathologic processes such as embryogenesis (type 1 EMT), wound healing and/or fibrosis (type 2 EMT) and malignant tumors (type 3 EMT). The proliferation rate, metastasizing and recurrence capacity, as also the individualized response at chemotherapics, in both epithelial and mesenchymal malignant tumors is known to be influenced by reversible switch between EMT and mesenchymal-to-epithelial transition (MET). Although much research work has already been done in these fields, the specific molecular pathways of EMT, relating to the tumor type and tumor localization, are yet to be elucidated. In this paper, based on the literature and personal experience of the authors, an update in the field of EMT vs MET in epithelial and mesenchymal tumors is presented. The authors tried to present the latest data about the particularities of these processes, and also of the so-called endothelial-to-mesenchymal transition, based on tumor location. The EMT-angiogenesis link is discussed as a possible valuable parameter for clinical follow-up and targeted therapeutic oncologic management. The paper begins with presentation of the basic aspects of EMT, its classification and assessment possibilities, and concludes with prognostic and therapeutic perspectives. The particularities of EMT and MET in gastric and colorectal carcinomas, pancreatic cancer, hepatocellular and cholangiocarcinomas, and lung, breast and prostate cancers, respectively in sarcomas and gastrointestinal stromal tumors are presented in detail.
Core tip: This review, based on the personal experience of gastrointestinal pathologists, which correlates with literature data, is intended to provide an up-date in the field of epithelial-mesenchymal transition and mesenchymal-epithelial transition in epithelial and mesenchymal-malignant tumors, respectively. The molecular mechanism of these processes and their possible role in tumor progression, metastasis and therapy are presented in detail.