The spread of cancer in the organism facts and problems

In this review, cancer is conceived as an alteration of the surface-monitored social behavior of cells. Apart from impaired growth control, loss of residency (tissue affiliation) is the most important consequence of this homeostatic disorder. It results in local spread (penetration) which is initiated by locomotive and/or destructive activities of the neoplastic cells. Access of cancer elements to the circulation possibly leads to distant spread (metastasis). Penetration and metastasis largely depend upon reactions of the organism, which are of an ill-understood, ambiguous nature favoring both the tumor and the host.