Cancer benign cause


Modificările funcţionale ale celulelor canceroase în raport cu celulele normale

The human body is composed of cancer benign cause of cells, which constantly grow, divide and die. For the most part, cells are healthy and perform vital functions, but sometimes they do not form or behave properly.

Cancer begins when an abnormal cell grows and does not stop dividing. Cancer cells also do not obey the laws of contact inhibition, which means that cancerous cells propagate when they touch another cell normal cells stop dividing when this happens.

Functional changes of cancerous cells in relation to normal cells

This proliferation of cancerous cells enables the disease to quickly form tumors and spread throughout the body. Keywords cancer, cell cycle, type of tumors, genetics of cancer Rezumat Scopul acestui articol este de a explica ce modificări funcţionale apar atunci când celulele normale se transformă în celule can­ceroase.

Papilloma and breast cancer risk uman este alcătuit din trilioane de celule care cresc, se divid şi mor. Majoritatea celulelor sunt sănătoase şi îndeplinesc funcţii vitale, dar uneori celulele nu se comportă cancer benign cause. Cancerul debutează atunci când celulele cresc anormal şi nu se mai opresc din multiplicare.

Modificările funcţionale ale celulelor canceroase în raport cu celulele normale

Celulele can­ce­roase nu se supun regulii inhibiţiei de contact, ceea ce în­seam­nă că ele se vor multiplica chiar dacă vor fi în contact cu alte celule celulele normale se opresc din divi­ziu­ne atunci când sunt în contact cu o altă celulă. Această pro­li­fe­ra­re a celulelor canceroase permite formarea tumorilor şi răs­pân­di­rea lor în organism.

Cuvinte cheie cancer ciclu celular tipuri de tumori genetică oncologică Introduction Why does a normal cell suddenly become a foreign for the body, breaking the rules, dividing cancer benign cause, invading other tissues, usurping resources, and in some cases eventually killing the body in which it lives?

To understand how and why cells rebel, cancer benign cause need to understand the normal functions of cell growth and reproduction. Research in cell biology, biochemistry and molecular biology has provided astonishingly detailed information about the molecules cancer benign cause processes that allow cells to divide, grow, differentiate and cancer benign cause their essential functions.

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This basic knowledge of cell biology has also led to practical discoveries about the mechanisms of cancer. Specific molecules that control the progression of a cell through the cell cycle regulate cell growth. An understanding of normal cell cycle processes and how those processes go awry provides key information about the mechanisms that trigger cancer.

The loss of control of the cell cycle is one of the critical steps in the development of cancer.

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Although cancer comprises at least different diseases, all cancer cells share one important characteristic: they are abnormal cells in which the processes regulating normal cell division are disrupted. That is, cancer develops from changes that cause normal cells to acquire abnormal functions.

These changes are often the result of inherited mutations cancer benign cause are induced by environmental factors such as UV light, X-rays, chemicals, tobacco products and viruses.

All evidence suggests that most cancers are not the result of one single event or factor. Rather, around four to seven events are usually required for a normal cancer benign cause to evolve through a series of premalignant stages into an invasive cancer.

Often many years elapse between the initial event and the development of cancer. The development of molecular biological techniques may help cancer benign cause the diagnosis of potential cancers in the early stages, long before tumors are visible.

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What is cancer? Cancer results from a series of molecular events that fundamentally alter the normal properties of cells.

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In cancer cells, the normal control systems that prevent cell overgrowth and the invasion of other tissues are disabled. These altered cells divide and grow in the presence of signals that normally inhibit cell cancer benign cause, therefore they no longer require special signals to induce cell growth and division. As these cells grow, they develop new characteristics, including changes in cell structure, decreased cell adhesion and production of new enzymes.

These heritable changes allow the cell and its progeny to divide and grow, even in the presence of normal cells that typically inhibit the growth of nearby cells.

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Such changes allow the cancer cells to spread and invade other tissues. The abnormalities in cancer cancer benign cause usually result from mutations in protein-encoding genes that regulate cell division.

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Over time, more genes become mutated. This is often because the genes that make the proteins that normally repair DNA damage are themselves not functioning cancer benign cause because they are also mutated.

Consequently, mutations begin to increase in the cancer benign cause, causing further abnormalities in that cell and the daughter cells. Some of these mutated cells die, but other alterations may give the abnormal cell a selective advantage that allows it cancer benign cause multiply much more rapidly than the normal cells.

A benign tumor near your brain stem is causing your condition. O tumoră benignă lângă trunchiul cerebral îți cauzează boala. Notice the adenoma, benign tumor, in the parathyroid gland.

This enhanced growth describes most cancer cells, which have gained functions repressed cancer benign cause the normal, healthy cells. As long as these cells remain in their original location, they are considered benign; if they become invasive, they are considered malignant.

Cancer cells papilloma nasale invertito malignant tumors can often metastasize, sending cancer cells to distant sites in the body where new tumors may form. Genetics of cancer Alterations in the same gene are often 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 cancer benign cause that normally prevent cell division or cause cell death.

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The third group contains DNA repair genes, which help prevent mutations that lead to cancer. 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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In normal cells, proto-oncogenes code for the proteins that send a signal to the nucleus to stimulate cell division. These signaling proteins act in a series of steps called signal transduction cascade or pathway. This cascade includes a membrane receptor for the signal molecule, intermediary proteins that carry the signal through the cytoplasm and transcription factors in the nucleus that activate the genes for cell division.

In each step of the pathway, one factor or protein activates the next; however, some factors can activate more than one protein in the cell. Oncogenes are altered versions of the proto-oncogenes that code for these signaling molecules. The oncogenes activate the signaling cascade continuously, resulting in an increased production of factors that stimulate growth 1,2. Cell cycle An initial appearance of malignant transformation is represented by the disturbance of cell divizions.

Normal cancer benign cause grow and divide in accordance with the cell cycle. Mutations in proto-oncogenes or in tumor suppressor genes allow a cancerous cell to grow and divide without the normal controls imposed by the cell cycle. The major events in the cell cycle are described in Figure 1. Figure 1.