Figure 1.

Genes and pathways involved in the tumor progression toward cancer metastasis. Metastasis is the final stage of a chronic tumor progression, starting from tumor transformation followed by early progression within the primary tumor tissues, blood-borne to become circulating tumor cells (CTCs), colonization into distant organs in which pre-metastatic niche has been built, and outgrowth as secondary tumor tissues. Listed are signaling pathways associated with intrinsic and extrinsic stimulations for apoptosis and with apoptosis-independent activities. Note: The genes marked in green are considered tumor suppressive and in red oncogenic. The arrows with broken lines indicate the directions and locations toward which particular cells are moving. The corresponding full names abbreviated are listed as follows: TMEs, tumor microenvironments; ECM, extracellular matrix; micro, micrometastasis; macro, macrometastasis; FN, fibronectin; BMDC, bone marrow derived cells; TNF, tumor necrosis factor family, ptw, pathway; mig, migration; inv, invasion.