What is cancer?
Cancer (also, terms such as malignant tumor or neoplasm) is a disease of any group of diseases characterized by uncontrolled, abnormal growth of cells that can spread throughout the body. It is believed that cancer develops from a single cell or a small group of cells following changes occurred in their DNA – the genetic material that instructs cells behavior.
Some cancers are due to genetic abnormalities, due to the action of other carcinogens, environmental agents capable of causing genetic mutations. Sometimes viruses interact with the genes of cells and increase their chance of becoming cancerous. Often the reason for which the cell becomes cancerous is unknown.
No form of cancer or other forms of cancer is not contagious. Cancer is not transmitted by airborne droplets, sexual as well as household items. Patients who dignosed with cancer, requires the maximum attention and care. Not to alienate them from the superstitious beliefs of their infectiousness.
Cancer cells are dangerous in many ways. They can deprive normal cells of nutrients, space for growth, they can form a mass of cells, the tumor, which can infiltrate and destroy normal tissue and may metastasize to other parts of the body through the blood or lymphatic vessels. Most cancers take years to develop, a cancer patient, detected and cured prior to germination in adjacent organs and metastasis to the whole body, has the greatest chance for cure.
Distinguish between malignant tumors of epithelial nature, and arising from the mesenchymal derivatives – sarcoma.
Epithelium – the tissue that covers the surface of the skin, cornea, and lining all cavities of the body, the inner surface of the hollow organs of the digestive, respiratory and genitourinary systems. Epithelium is protective and is involved in metabolism. Typically, epithelial cells lying close to each other, forming a (single-layer epithelium) or multiple (stratified epithelium) layers.
Mesenchyme – the embryonic connective tissue of most multicellular animals. Mesenchyme arises from cells that are evicted from the different germ layers: ectoderm, endoderm and mesoderm. From the mesenchyme are formed: proper connective tissue, blood vessels (endothelium them), blood cells, the major muscles, visceral skeleton, pigment cells and connective tissue of the lower layer of the skin.
Up to 90% of all malignant tumors are carcinomas. Therefore, all malignant tumors are called cancer.
It is believed that the reason for the appearance of cancer cells – mutations in normal cells. The immune system tries to kill mutated cells in a timely manner. But sometimes (if the immune system is weakened or altered cells are produced in large quantities), it can not cope with this task.
Malignant tumors grow much faster than benign. Cells of these tumors are divided into uncontrolled, are capable of invasion (sprouting) in the adjacent tissue and metastasize to distant organs (blood or lymph cancer cells can travel to lymph nodes or distant organs and form secondary foci where tumor – metastasis).
There are four common types of cancer treatment: surgery, radiotherapy, chemotherapy and biotherapy (helping patient’s immune system to cope with cancer). Many people get the combined treatment. Different types of cancer different rates of growth, the nature of metastasis and response to treatment. Cancer patients need treatment, corresponding to a strictly defined disease and only in specialized clinics.
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