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Cancer (Cancer) (Latin cancer, carcinoma, from the Greek karkinos - cancer, crab) - a malignant tumor of the epithelium, that is, from the tissue covering the outside of the living organism and its lining from the inside, as well as forming his prostate. Therefore, the cancer - a malignant tumor (neoplasm, blastoma) of the skin, digestive tract, respiratory and urinary tract, lung, kidney, liver, reproductive organs and glands. The name given to the doctors of the Middle Ages, due to the appearance of the tumor, cancer or a crab-like. Cancer is the vast majority of all human malignancies, which also include numerous sarcoma, hematological malignancies, glial, and other bone tumors. In some countries a cancer refers to any malignant neoplasm.
The tumor arises from metabolic processes in cells and monitoring the attenuation of intracellular processes by the organism. As a result of the acquisition of new skills and the partial independence of the regulatory systems of the body, young dividing cells lose their ability to differentiate - they do not get the proper function and not form the normal operating fabric. Not participating in the life of the organism, these cells become useless to him superfluous. The body tries to get rid of them with the help of immune responses, which are not always effective. Excess young, breeding all the time, but not working cells, besides requiring an increasing amount of energy and food resources, leads to the fact that these cells are attacked on the rocks of the tissue or organ. These cells (they are called tumor) embedded in the fabric body infiltrate (sm. infiltrate) and destroy them, grab the blood and lymph vessels, which are distributed throughout the body - metastasize (sm. metastasis).
The reasons for the appearance of the tumor is known, not all. A predisposition to cancer of an organ (eg, breast, stomach) is inherited, that is, runs in families. Inherited hormonal abnormalities in the body or local structural damage to any organ (intestinal polyposis, birthmarks on the skin and so on. D.). These deviations and wrong and can lead to tumor development, noted that more than a hundred years ago, the German pathologist Julius Friedrich Kongeym. However, for the appearance of tumors - oncogenesis - some tissue deformities enough. Needed mutagenic stimuli, causing changes in the genetic apparatus of the cell, and then the tumor transformation. Such incentives may be internal (e.g., increased production of hormones or other metabolites, their imbalance) or external -.. By physical (e.g., ionizing or ultraviolet radiation), chemical, viral, etc. These factors are mutagenic and thus carcinogenic, that triggers the mechanism that produces the cancer cells in increasing numbers.
it is believed that the program has a tumor any cell. This program is recorded in a specific genes - oncogenes. Under normal circumstances, oncogenes rigidly blocked (repressed), but under the influence of mutagens block can be removed, and oncogenes have the opportunity to work. It is also known that many carcinogens inhibit the body's immune system, freeing it from the hard and continuous monitoring of deviating from the norms of the cells. Control and restoring immune system function sharply weaken in old age, when most often appear malignant tumor.
Cancerous tissue is a very moving and changeable education. Its behavior depends on many factors, including the intensity of protective anti-reactions, which body is capable in a particular case. The human immune system may partially or completely destroy the tumor. It can also block the cancer cells at an early stage and to give them opportunities to penetrate deep into the body (a non-invasive cancer, or "carcinoma in situ» - «in situ»). In cancers name reflects: belonging to a particular organ (lung cancer, ovarian cancer, etc...), The type of epithelium that serves tumor source (cancer squamous, glandular - adenocarcinoma, basal, etc...), Growth rate , histological equivalent of which is the degree of maturity of the cancer tissue (cancer differentiated and undifferentiated), the properties associated with the degree of tumor maturity and efficient immune responses in it (an aggressive cancer, stable, regression).
Symptoms of cancer appears relatively late, when the tumor reaches significant proportions and disrupts organ function, which is growing. If the hollow body, may disrupt its continuity, there are pathological (inflammatory or otherwise) allocation, possible bleeding. The patient feels weak, loses weight, his body temperature rises, it experiences pain, increased erythrocyte sedimentation rate.
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