Metastasis - Characteristics Define Cancer
Metastasis is the capability of a malignant cell to detach itself from a tumor and establish a tumor in another site. This capability reflects the lack of contact inhibition seen in cancer cells in tissue culture. It as well shows that malignant cells have the capability to sustain themselves when circulating freely in the blood stream or lymph ducts. Metastasis as we have mentioned previous is the diagnostic feature of cancer cells and distinguishes malignant growth from benign growth. The mechanism through which a malignant tumor initially penetrates and invades the normal surroundings tissue is thought to comprise three steps.
1) The tumor cells then move through the defect in the membrane and the process is repeated till they reach the blood stream or lymph vessels.
2) The basement membrane is then lysed by proteases found in cancer cells.
3) The cancer cell first acquires the ability to bind a component of the basement membrane of the tissue of origin i.e., receptors bind to tissue matrix components.