Abstract
An epithelial-to-mesenchymal transition (EMT) is thought to be an important process in the acquisition of capabilities required for metastasis. Until recently, studies of EMT involved mostly in vitro assays and transplantation experiments of cancer cells that overexpressed known EMT drivers. While valuable, these studies do not allow us to conclude if an EMT sustained under "physiologic conditions" within the tumor microenvironment leads to the myriad changes in phenotype observed in vitro. Here we review our recently published work using a lineage labeled genetically engineered mouse model of pancreatic ductal adenocarcinoma to characterize cells that have sustained an EMT in vivo.