**2.3 Motility**

Actin filament assembly and treadmilling through coordinated polymerization and depolymerization provide cellular locomotion. However, tumor cells stimulate motility through lysophospholipase D in an autocrine fashion. *C-met* and hepatocyte growth factor interact and induce invasive epithelial cells chemokinetic activity. Chemotactic/haptotactic effect correlates to directional motility [1, 6]. Structures so called invadopodia determined in invading cells and represent the physical convergence of adhesion, proteolytic, and motility components of invasion. Therefore, invapodia is the essential structure for cancer invasion; however, if a tumor cell can not complete subsequent steps, it cannot go through metastasis [1].

#### **2.4 Intravasation**

Entry of a tumor cell into either blood or lymphatic vessels by serine and metalloproteinase action is called intravasation. After proteinase activity, tumor cells pass
