Called the excess growth of tumor tissue consisting of cells, the pathologically altered under the influence of various environmental factors. All tumors are divided into benign and malignant.
A benign tumor does not extend beyond tissue, characterized by slow growth, lack of inclination to mestastazirovaniyu. The appearance of tumor tissue (histological structure) differs little from the surrounding healthy tissue. With its growing benign tumor can obstruct, compress the surrounding tissue, which often leads to the need to remove it. Sometimes under the influence of different environmental factors is subjected to a benign tumor malignancy (malignization).
Examples of benign tumors are fibroma arising from the connective tissue, uterine (from muscle), lipoma (from fat), osteoma (of bone). After surgery, excision of benign tumor and its shell comes complete cure, and current endoscopic surgical procedures, regardless of tumor size allow the patient the next day after the intervention to be on their feet.
Malignant tumors of the
Malignant tumor has no shell, is growing rapidly, its individual cells and cell cords are capable of infiltrative growth (penetration into the surrounding tissue with damage to the structure), as well as dissemination (the spread or spacing to distant organs and tissues through the blood and lymphatic vessels). Dissemination is made possible by germinating in the tumor vessel. The consequence is the formation of metastasis dissemination - next to the body or the remote. Histological structure of malignant tumors is significantly different from the surrounding healthy tissue. Her atypical cells (not like the cells of healthy organs and tissues), polymorphic (diverse in mind), many are in mitosis (the process of fission). A characteristic feature of tumor tissue is anaplasia, ie the similarity of tumor cells with embryonic cell. However, tumor cells are not identical to embryonic as their growth is not accompanied by differentiation. The consequence is a lower degree of differentiation, in particular, the loss of original functionality.
Healthy cells are not transformed itself into the tumor. To do this, the impact of physical, chemical, or biological factors that lead to a change in genetic information - mutation. In other words, the main cause of malignant tumors is exposure to adverse environmental factors.
Carcinogenesis - a process of transformation of normal cells into malignant. The process of malignant growth is rather complicated, multistep, and therefore does not always lead to the development of actual disease. Moreover, we know that at any given time in the human body contains millions of cells with altered genetic information. But thanks to the efficient and duplicated DNA repair systems, the launch of apoptosis (programmed cell death) in reparations failed, clear the immune system and other defense mechanisms of tumor growth is likely minimal. In tumor growth distinguish several stages: Initiation. The process of change in the genome of the target cell under the influence of environmental factors. In this single mutation is not enough. Changes are needed in at least two genes, one of which provides the immortality of cells and the other - the actual development of the malignant phenotype.
Promotion. At this stage there is an increase of cell populations with changes in the genome and are under the influence of promoters of carcinogenesis. As a result, a growing population and the mutated cells. This pre-cancerous stage is reversible, since possible regulation of the promoter, which can trigger further changes in the genome.
Progression. At this stage, the active growth of mutated clones of cells, which leads to the formation of tumors. A decrease in the degree of cell differentiation, expression of invasive properties and, consequently, the ability to metastasize.
The first stage is extremely difficult to identify today. The second stage can often be detected by regular examination of a targeted risk groups. This concerns the identification of different markers of precancerous disease (clinical and laboratory). Unfortunately, the phase progression in the early stages is often asymptomatic, and the success of treatment depends on early detection of tumors.
Among the methods of treating tumors secrete surgery, chemotherapy and radiation. Indications and efficacy of each of them, or a combination depends on the type and stage of tumor development.