Malignant Tumors


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Malignant Tumors

 

growths of cells that have lost their normal properties and communication with the body and have the capacity, while invading surrounding tissues, to disrupt them and produce metastases—that is, to transport themselves into other organs and tissues and form secondary tumor foci.

Malignant tumors include sarcomas, malignant tumors of connective tissue; cancer, malignant tumors that develop from epithelial tissue; and some forms of leukoses. They are found in man and animals. With the rise in average longevity in countries where medicine is highly developed, malignant tumors are diagnosed in more cases; they are the second greatest cause of death (after cardiovascular diseases).

External causes of malignant tumors may be certain radiations and chemical substances (carcinogenic substances); internal causes may be disturbances of metabolism and hormone balance. A number of tumors in animals are caused by viruses.

Treatment of malignant tumors includes surgery, radiation, and medication (and their combinations). Prophylaxis calls for decreasing the level of harmful influences on the body and the timely discovery and cure of so-called precancerous or preneoplasmic changes and early forms of malignant tumors.

L. M. SHABAD

References in periodicals archive ?
A significant risk of malignant tumors is that cancer cells can spread, or metastasize.
An appendix handily includes TNM classification of primary malignant tumors.
The study, conducted between 1988 and 1997, surveyed 61 hospital patients who were exposed to radiation from the bombings before they were born and were suspected of having malignant tumors such as cancer, hospital officials said.
The programs include a liver-specific agent for use in detecting cancer that has spread to that organ and a tumor-enhancing MRI agent with increased sensitivity and potential to distinguish benign tumors from malignant tumors.
The arsenic-transformed cells had been exposed continuously to sodium arsenite and, after 29 weeks of exposure, produced malignant tumors when inoculated into nude mice.
2% of all head and neck malignancies and approximately 1% of all laryngeal malignant tumors, although it is the most common nonepithelial neoplasm of the larynx.
Indeed, more-severe lesions appeared as the mice aged, and, in a few old mice, the lesions gave rise to highly malignant tumors.
Differences in the numbers of these cell types between benign and malignant tumors were compared using the nonparametric Mann-Whitney statistical test.
NYSE: SYN) today announced that they have established an alliance for the purpose of discovering novel drugs for treatment of arthritic diseases and invasive malignant tumors and certain other diseases.
When lymphocytes, or white blood cells, which are responsible for defending the body against infection, divide and multiply uncontrollably, malignant tumors can form.
Although most tumors that originate in the external auditory canal are benign inflammatory polyps related to ear infections, a variety of other benign and malignant tumors occur there as well.