Inducers of epithelial mesenchymal transition and cancer stem cells in malignant pleural effusions

The Epithelial to Mesenchymal Transition (EMT) plays a role not only in tumor metastasis but also in tumor recurrence. This process is believed to be tightly linked to the presence of Cancer Stem Cells (CSCs) however, it is still not clear which factors could induce EMT and how it could be a source for CSCs. It has been demonstrated that Malignant Pleural Effusion (MPEs) may represent an excellent source to identify markers and molecular mechanisms involved in EMT and CSCs development. Growth factors, cell differentiation markers and molecular adhesion are involved in some of the crucial neoplastic cell events such as proliferation, metastasis, resistance to chemotherapy and EMT. In this review, we summarize the current understanding of which molecular markers can orchestrate EMT and CSCs in MPEs.