Kalluri Legend

Figure 2. Mechanisms of metastasis. Epithelial-to-mesenchymal transitions and tumor microenvironment interactions are likely associated with the progression of cancer. Carcinoma of an epithelial origin may acquire a mesenchymal-like state in order to facilitate its migration and invasion. Upon reaching their metastatic sites, the cancer cells revert back to their epithelial state to form organized tumorigenic nodules. During EMT and MET, a bimodal communication exists between the host fibroblasts, extracellular matrix/basement membranes, and also the immune cells. Interactions with host elements also influence the progression of cancer at all stages. Changing dynamics in the composition of extracellular matrix can induce new signaling pathways within the cancer cell. Immune cells may also play a role in the progression of cancer - in some cases even protecting the cancer cell from apoptosis. How host cells are usurped by cancer cells to facilitate cancer progression and metastasis is not yet clear.

Journal of Cellular Biochemistry 101:816-829 (2007) "Reprinted with permission of Wiley-Liss, Inc. a subsidiary of John Wiley & Sons, Inc."