Below several differences between cancerous cells and normal cells will be

Below several differences between cancerous cells and

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Below, several differences between cancerous cells and normal cells will be discussed. Types of Cancer Cells There are as many types of cancer cells as there are types of cancer . Of the hundred plus types of cancer, each is named for the type of cancer cells in which it began. And just as cancers may behave differently from one another, not all cancer cells behave the same. How Do Cancer Cells Start? Cancer cells are usually formed after a series of mutations cause them to become increasingly abnormal. These mutations are either inherited or more often, caused by carcinogens (cancer-causing substances) in our environment. That cancer is caused by not one but several mutations explains why cancer is more common in older people and why it is often multifactorial (meaning there are several factors that work together to cause cancer.) It also helps explain a genetic predisposition to cancer. A genetic predisposition does not mean you will get cancer, but, simplistically, if a few mutations are already in place, it will likely take fewer acquired mutations for a cell to become cancerous.
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The process of normal cells becoming cancer often goes through stages in which the cell becomes progressively more abnormal appearing. These stages may include hyperplasia, dysplasia, and finally cancer. You may also hear this described as differentiation. Early on a cell may look much like normal cells of that organ or tissue, but as progression occurs, the cell becomes increasingly undifferentiated. This is, in fact, why sometimes the original source of a cancer cannot be determined. Genetics of Cancer Only a small number of the approximately 35,000 genes in the human genome have been associated with cancer. (See the Genomics unit.) Alterations in the same gene often are associated with different forms of cancer. These malfunctioning genes can be broadly classified into three groups. The first group, called proto-oncogenes, produces protein products that normally enhance cell division or inhibit normal cell death. The mutated forms of these genes are called oncogenes. The second group, called tumor suppressors, makes proteins that normally prevent cell division or cause cell death. The third group contains DNA repair genes, which help prevent mutations that lead to cancer. Proto-oncogenes and tumor suppressor genes work much like the accelerator and brakes of a car, respectively. The normal speed of a car can be maintained by controlled use of both the accelerator and the brake. Similarly, controlled cell growth is maintained by regulation of proto-oncogenes, which accelerate growth, and tumor suppressor genes, which slow cell growth. Mutations that produce oncogenes accelerate growth while those that affect tumor suppressors prevent the normal inhibition of growth. In either case, uncontrolled cell growth occurs.
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