Have a Reduced Need for Growth Factors

Have a Reduced Need for Growth Factors - invade neighboring...

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Have a Reduced Need for Growth Factors Growth factors are chemicals that stimulate cell division in normal cells by causing certain metabolic reactions to occur. Normally, cyclin combines with kinase only in the presence of growth factors. In cancer cells, cyclin may combine with kinase in the absence of growth factors. Some genetic mutations (called oncogenes , discussed below) allow these reactions to occur with reduced amounts of growth factors. The reduced need for growth factors may be responsible for the lack of contact inhibition and anchorage dependence discussed above. Ability to Penetrate the Lamina The lamina is a noncellular barrier that is attached to cells that line the surfaces, internal cavities, and organs (epithelial tissue). Normally, cells cannot penetrate this barrier and therefore cannot
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Unformatted text preview: invade neighboring tissues and organs. Cancer cells have the ability to penetrate the lamina. The cells are able to invade and destroy neighboring tissue. A benign tumor does not invade neighboring tissue. Angiogenesis Tumors need a blood supply for food and oxygen. Cancer cells release growth factors that cause nearby blood vessels to produce branches that grow into the cancerous tissue. Immune System The immune system can recognize foreign cells and invaders (bacteria, viruses, etc.) because they have proteins and other structures that are different from the body’s "self" markers. Cancer cells may have mutated "self" markers and are often destroyed by the immune system....
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