Astrocytoma, by its nature, refers to tumor processes that develop from brain cells. But not all cells are involved in the formation of a tumor, but only those that perform an auxiliary function. To understand what an astrocytoma consists of, let's delve a little into the physiology of the nervous system.
It is known that nerve tissue consists of 2 main types of cells:
- Neurons are the main cells that are responsible for the perception of stimuli, the processing of information coming from outside, the generation of nerve impulses and their conduction to other cells. Neurons can have different shapes and number of processes (axon and dendrites).
- Neuroglia are auxiliary cells. The name "glia" means "glue." This explains the functions of the neuroglia: they form a grid (skeleton) around the neurons and the blood-brain barrier between the blood and the neurons of the brain, feed the neurons and metabolism in the brain, control blood flow. If it were not for the neuroglia, any brain shake, not to mention serious injuries, would end badly for a person (the death of neurons, and hence the extinction of mental functions). Glial cells soften the blow, protecting our brain as well as the skull.
It is worth mentioning that neuroglia are a more numerous type of brain cells (about 70-80%) compared with neurons. They may have different sizes and vary in shape. Small neuroglia (microglia) perform phagocytosis, i.e. Absorb the obsolete cells (such a cleaning company in the nervous system). Larger neuroglia (macroglia) perform the functions of nutrition, protection and support for neurons.
Astrocytes (astroglia) - one of the varieties of macroglial glial cells. They have multiple processes in the form of rays, for which they are called radiant neuroglia. These rays form the skeleton for neurons, thanks to which the nervous tissue of the brain has a certain structure and density.
Despite the fact that the transmission of nerve impulses, due to which the nervous activity is carried out, is answered by neurons, there is an assumption that it is the amount of astrogly that predetermines the characteristics of memory and even intelligence.
It would seem that the tumor is formed from the rapidly multiplying cells, which means that the number of astrogly increases, which should lead to an improvement in mental abilities. In fact, the local accumulation of cells in the brain does not bode well, because the tumor begins to put pressure on the surrounding tissues and disrupt their functioning.
The human brain consists of different parts: the medulla, middle and diencephalon, cerebellum, pons, and the terminal brain, which consists of both hemispheres and the cerebral cortex. All these structures consist of neurons and the neuroglia surrounding them, i.e. A tumor can form in any of these areas.
There are astrocytes in both white and gray matter of the brain tissue (they differ only in the length of the processes, but perform the same functions). White matter of the brain is called pathways through which nerve impulses are transmitted from the center (CNS) to the periphery and back. The gray matter contains the central parts of the analyzers, the nuclei of the cranial nerves, the cerebral cortex. In whatever area a tumor is formed, it will press on the brain from the inside, disrupting the functionality of the nerve fibers passing nearby, disrupting the functioning of the nerve centers.
When we found out that an astrocytoma of the brain is nothing but a tumor formation, a clear interest may arise among readers: is astrocytoma a cancer or a benign tumor? I would not like to upset our readers, because the disease is not as rare as one would expect, but this tumor is prone to degeneration into cancer, although the degree of malignancy largely depends on its type. Some neoplasms are characterized by slow growth and are quite amenable to surgical treatment, others are characterized by rapid growth and not always a good prognosis.
Astrocytomas can vary in shape and size, some do not have clear outlines, can sprout into other brain tissues. Within the nodal tumors (tumors with clear contours and localization), single and multiple cysts (cavities with semi-liquid contents) can be found. The growth of such tumors occurs mainly due to an increase in cysts, which causes squeezing of nearby brain structures.
Nodular tumors, although they can reach large sizes, are usually not prone to rebirth. They can be attributed to the category of benign tumors that can develop into a purely theoretical cancer.
Another thing astrocytomas prone to diffuse growth, i.e. Those that capture nearby tissue, metastasize to other brain structures and neighboring tissues. They usually have a fairly high degree of malignancy (3-4 degrees), over time acquire enormous size, since they are initially prone to growth, like any cancer tumor. Such tumors tend to turn from benign to malignant quickly, so they should be removed as early as possible, not focusing on the severity of the symptoms.
Scientists already know quite a lot about glial tumors consisting of astrocytes: their types, possible localizations and consequences, behavior, the ability to develop into cancer, treatment options, a tendency to relapse, etc. The main question remains a mystery, astrocytes begin to behave inadequately, which causes them to multiply vigorously, i.e. Mechanism of formation and development of the tumor process. The pathogenesis of astrocytoma of the brain remains unclear, and this is an obstacle to the development of methods for the prevention of the disease, the treatment of which requires a neurosurgical operation. The molecular pathogenesis of astrocytic tumors in children is being actively studied. ,  And we know that surgery on the brain is always a risk, even if the surgeon is highly competent.
Various pathways of genetic changes were found during the progression of primary glioblastomas, characterized by increased / overexpression of EGFR and PTEN mutations, while, on the contrary, secondary glioblastomas developing in younger patients show frequent mutations of p53. , 
Recent studies have shown that primary glioblastomas appear to be characterized by a loss of heterozygosity (LOH) 3 across chromosome 10, while secondary glioblastomas predominantly show LOH on chromosomes 10q, 19q and 22q , 
Genomic association studies have identified hereditary risk alleles in 7 genes that are associated with an increased risk of glioma.