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Cancer And Begins Essay

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Outline

I.Introduction

a.What is Cancer?

b.Conditions on which cancer begins.

c.Two Gene Classes

i.Proto-oncogenes

ii.Tumor Suppressor Genes

II.Signaling Systems go Wrong

a.Oncogenes

i.Ras family

1.Ras proteins

ii.Myc family

III.Tumor Suppressors Stop Working

a.Malignant Cells

i.TGF-B

ii.DPC4

iii.p15

iv.NF-1

IV.The Clock is Struck

a.The Cell Cycle

i.Mitosis

b.CDKs

V.Conclusion

How cancer develops is no longer a mystery. During the past two decades, researchers have made amazing progress in identifying the deepest bases of the process, those at the molecular level. These discoveries are forceful. They will survive the scrutiny of the future generations of researchers and for the form the foundation for revolutionary approaches to treatment. In reality, the term "cancer" refers to more than a hundred different forms of disease. Almost every tissue in the body can produce malignancies, some even produce several types. Furthermore, each cancer has unique features. Still, the basic resources that produce these diverse tumors appear to be quite similar.

The thirty trillion cells of the normal, healthy body live in a complex inter-reliant condominium, regulating one another's production. Certainly normal cells reproduce only when instructed to do so by other cells in their area. Such constant collaboration ensures that each tissue maintains a size and style appropriate to the body's needs. In contrast, cancer cells violate this system. They become ignorant to the usual controls on production and follow their own internal agenda for reproduction. They also possess an even more dangerous property - the ability to migrate from the site where they began, taking over nearby tissues and forming masses at distant sites in body. Tumors composed of such malignant cells become more and more aggressive over time, and they become fatal when they disrupt the tissues and organs needed for the survival of the organism as a whole (Silva, 8).

All this is not new. But over the past twenty ears, scientists have discussed a set of basic principles that govern the development of cancer. It is now known that the cells in a tumor come from a common ancestral cell that at one point (usually decades before a tumor becomes perceptive) initiated a series of inappropriate reproduction. In addition, the malignant transformation of a cell comes about through the build-up of mutations in specific class of the genes within it. These genes provide the key to understanding the process at the root of human cancer.

Genes are carried in the DNA molecules of the chromosomes in the cell nucleus. A gene specifies a sequence of amino acids that must be linked together to make a particular protein, the protein then carries out the work of the gene. When a gene is switched on, the cell responds by synthesizing the encoded protein. Mutations in a gene can upset a cell be changing the amounts of the activities of the protein product (Vogelstein, 43).

Two gene classes, which together represent only a small proportion of the full genetic set, play major roles in the triggering of cancer. In their normal arrangement, they compose the life cycle of the cell- the complex sequence of events by which a cell enlarges and divides. Proto-oncogenes encourage such growth, while tumor suppressor genes hinder it. Together these two gene classes account for much of the uncontrolled cell production seen in human cancers (Vogelstein, 44).

When proto-oncogenes are mutated they can become carcinogenic oncogenes that force excessive multiplication. The mutations may cause the proto-oncogenes to yield too much of its encoded growth-stimula...

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