Explain the Characteristics of Cancer?

The important characteristics of cancer are excessive cellular multiplication, invasiveness and autonomy. The active process of invasion is known as metastasis. Metastasis requires specific surface receptors, enzymes, protein synthesis and use of energy. The process of invasion is described briefly below: Metastatic cell penetrates the extra cellular matrix that surrounds the tumor and travels through the tissue until it reaches a blood vessel or a lymphatic vessel wall. It dissolves a portion of the wall and then propels itself through the circulating blood. At distant site, the tumor cell again re-attaches to blood vessel wall and repeats the process until it settles down and begins to form a new tumor. Tumor cells gain growth autonomy by either activation of growth promoting antigens or loss of growth inhibitory cancer suppressor genes. The cancer suppressor genes are called antioncogenes. You may be little confused about the usage of the terms tumor and cancer.