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Tumor cells: what is it, properties, features
Last reviewed: 23.04.2024
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Today many people are asking themselves what are the tumor cells, what is their role, are they dangerous and are they of benefit, or are they solely aimed at destroying the macroorganism? Let's figure this out.
Transformed cells that form a malignant tumor. Cells undergo numerous changes. These changes are noticeable at the morphological, chemical, and biochemical level. Some are visible even to the naked eye. Detection of others requires special equipment. It all depends on the type and location.
A distinctive feature is the ability to infinitely increase its biomass, which is due to a violation of apoptosis (provides programmed death). This growth ends only with the death of a person.
Difference of a tumor cell from normal
There is a system of cellular apoptosis, which is a programmed death of the cell link. Usually a cell that has passed its life cycle dies. In its place a new subpopulation of the cell cycle develops over time. But with cancer transformation such a natural mechanism is disrupted, as a result of which this cell does not die, but continues to grow and function in the body.
It is this internal mechanism that is the basic basis of tumor formation, which has a tendency to uncontrolled and unlimited growth. That is, in fact, this kind of cellular structure is a cell that is not capable of death, and has unlimited growth.
Cellular atypism and atypical cells
By atypical cells are meant cells that are susceptible to mutation. Most often, atypical cells are formed under the influence of various external factors, or heredity, by transforming them from stem cells. Most often, the trigger factor for the development of a tumor cell is a specific gene that codes for cell death. Some potentially oncogenic viruses, for example retroviruses, herpesviruses, are capable of causing the transformation of stem cells into cancer cells.
Cellular atypism is the actual process of transformation, to which healthy cells are exposed. This process involves a complex of chemical and biochemical processes. Mutation is carried out under the condition of immune system disorders, especially in autoimmune diseases, in which the function of the immune system is transformed in such a way that it begins to produce antibodies directed against the cells and tissues of its own organism. The development of cellular atypism is aggravated by the deterioration of the body's natural defenses, in particular, when the activity of T-lymphocytes (killers) is disturbed, the processes of cell death are violated, which leads to their malignant degeneration.
[6], [7], [8], [9], [10], [11]
Carcinogenesis
The process of potential growth of tissues, which in no way is associated with the normal state of the body. Carcinogenesis involves the process of the degeneration of a normal cell into a tumor cell, which is a local formation, but the whole organism is involved. Characteristics - tumors can give metastases, endlessly expand.
[12], [13], [14], [15], [16], [17], [18]
Cancer cell under a microscope
At the heart of the cancer cell development is a sharp increase in the nucleus. A cancer cell can be easily detected under a microscope, since the nucleus in it can occupy most of the cytoplasm. Also, the mitotic apparatus is clearly pronounced, and its disturbances are noticeable. First of all, attention is drawn to the presence of chromosomal aberrations, non-disjunction of chromosomes. This leads to the formation of multinucleated cells, the increase and thickening of the nucleus, their transition to the phase of mitotic division.
Also, under a microscope, deep invaginations of the nuclear membrane can be detected. In electron microscopy, intranuclear structures (granules) are seen. Also in the course of light microscopy, it is possible to detect a loss in the clarity of the nuclear contours. Nucleocytes can maintain a normal configuration, can increase to a quantitative and qualitative ratio.
There is a swelling of the mitochondria. At the same time, there is a decrease in the number of mitochondria, mitochondrial structures are violated. There is also a diffuse arrangement of the ribosomes relative to the endoplasmic reticulum. In some cases, the Golgi apparatus may completely disappear, but in some cases its hypertrophy is also possible. There is also a change in subcellular structures, for example, the structure changes, the appearance of lysosomes, ribosomes. In this case, there is a different degree of differentiation of cellular structures.
In the course of microscopy, it is possible to identify low-grade and highly differentiated tumors. Low-differentiated tumors are pale cells, which contain a minimal amount of organelles. Most of the cellular space is occupied by the cell nucleus. In this case, all subcellular structures have a different degree of maturity and differentiation. For highly differentiated tumors, the original tissue structure is characteristic.
Properties and characteristics of tumor cells
If the cell becomes tumor, it breaks down its genetic structure. This entails repression. As a result of the derepression of other genes, the appearance of modified proteins, isoenzymes occurs, and cell division also occurs. This can change the intensity of gene and enzyme functioning. Often there is a repression of protein components. Previously, they were responsible for the specialization of the cell, activated by depression.
Tumor cell transformation
Elements that act as triggers that trigger the pathological process. There is an assumption that the introduction of chemicals is carried out directly in DNA and RNA cells. This contributes to impaired maturation, an increase in cell permeability is developed, as a result of which potentially oncogenic viruses are able to penetrate into the cell.
Also, some physical factors, such as elevated levels of radiation, radiation, mechanical factors, can become triggers. As a result of their impact, the genetic apparatus is damaged, cell cycle disorders, mutations.
The consumption of amino acids sharply increases, anabolism increases, whereas catabolic processes decrease. The glycolysis increases dramatically. There is also a sharp decrease in the number of respiratory enzymes. There is also a change in the antigenic structure of the tumor cell. In particular, it begins to produce the protein alpha-fetoprotein.
Markers
The easiest way to diagnose cancer is to take a blood test to identify cancer markers. The research is carried out quite quickly: 2-3 days, in case of emergency it can be performed in 3-4 hours. In the course of the analysis, specific markers are identified that indicate the course of oncological processes in the body. By the type of the marker identified, it is possible to talk about what type of cancer occurs in the body, and even determine its stage.
Atipizm
It should be understood that the cell is not capable of death. It can also give pathological metastases. Also characterized by a violation of synthetic processes, intensively absorbs glucose, quickly breaks down proteins and carbohydrates, changes the action of enzymes.
Genome
The very essence of transformational changes is the activation of the synthesis of nucleic acids. The standard complex undergoes significant changes. The synthesis of DNA polymerase-3, which is responsible for the synthesis of new DNA on the basis of native structure, is reduced. Instead, synthesis of similar type 2 structures is enhanced, which is capable of restoring DNA even on the basis of denatured DNA. This is what ensures the specifics of the elements under consideration.
Receptors
The most well-known is the epidermal growth factor receptor, which is a transmembrane receptor. There is active interaction with epidermal growth factors.
Immunophenotype
Any transformation entails a change in the genotype. This is clearly expressed in changes that are reflected in the phenotypic level. Any change of this kind is alien to the body. This implies excessive aggressiveness of the human immune system, which is accompanied by an attack and destruction of the body's own tissues.
Expression of tumor cells
Expression is due to several reasons. In primary carcinogenesis, only one cell is involved, but sometimes there can be simultaneous involvement of several cells in this process. Then the tumor develops, its growth and reproduction takes place. Often the process is accompanied by spontaneous mutations. Tumors acquire new properties.
A distinctive feature is the ability to express genes that act as growth factors for the tumor. They completely change the metabolic processes of the original cell, subordinating it to their needs, acting as a kind of parasite.
[24], [25], [26], [27], [28], [29], [30], [31]
Diffuse expression
For active cell division, a presence in the blood, a constant expression of the factor that suppresses (represses) the activity of the gene is required.
[32], [33], [34], [35], [36], [37], [38], [39]
Absence of expression
During the differentiation of mutated tissue, it loses its ability to express a reducing gene, which is responsible for programmed apoptosis. The loss of this ability, deprives the corresponding structure of the possibility to cease to exist. Accordingly, it continuously grows and multiplies.
Proliferation of tumor cells
Proliferation is an indicator of growth, determines severity and stage. Functional anaplasia is observed. In fast-growing tumors, all the initial properties of the tissue are completely lost.
Proliferation index
The indicator depends on the location of the localization. It is determined by the expression of Ki-67. It is expressed as a percentage by determining the ratio between the number of normal cells and the number of tumor cells. It is expressed as a percentage, where 1% is the minimum amount, the early stage of the tumor process. 100% - the maximum stage, as a rule, is found out at a lethal outcome.
Individuality
They are transformed cells that have undergone mutational processes. Also in these cells, the ability to transform the basic properties of the original cell is clearly expressed. A distinctive feature is the inability to die and the ability for unlimited growth.
Uniformity
First of all, it is necessary to know that this phenomenon is nothing but a degenerated cell of the human body, which for various reasons has undergone a malignant transformation. Almost any healthy cell of the human body can potentially potentially be affected by this process. The main thing is the presence of trigger factor, which will trigger the mechanism of transformation (carcinogenesis). As such factors may be the virus, damage to the cellular or tissue structure, the presence of a special gene that codes for cancer degeneration.
Circulating tumor cells
The main feature of this cell is its biochemical cycle. There is a change in enzymatic activity. Also worth noting is the tendency to reduce the amount of DNA polymerase 3, which uses all components of the native DNA of the cell. Synthesis also changes significantly. The synthesis of proteins sharply increases, both qualitatively and quantitatively. Also of particular interest is the presence in the cancer cells of the coarcted squirrel protein. Normally, the content of this protein should not exceed 11%, with tumors the number increases to 30%. There is a change in metabolic activity.
Stem Cell Tumors
It can be said that these are primary, non-differentiated structures that will later undergo differentiation of functions. If such a cell undergoes a mutation and becomes cancerous, it becomes a source of metastasis, as it moves freely with the bloodstream, and is able to differentiate into any tissue. Lives long and slowly proliferates. When transplanted to a person with low immunity (immunodeficiency), can cause the development of malignant neoplasm
Apoptosis of tumor cells
The main problem of the tumor cell is that the processes of apoptosis (programmed death, incapable of death, and continues to grow and multiply) are violated in it. There is a gene that inactivates the gene that gives the cell immortality. This allows you to start again the processes of apoptosis, as a result of which you can establish normal cellular processes, and return the cell to its normal state, causing its death.
[50], [51], [52], [53], [54], [55], [56], [57]
Differentiation of tumor cells
Tumor cells differentiate depending on the composition of which tissues it enters. The names of tumors also depend on the names of the tissues that they are part of, as well as on the organ that underwent a tumor transformation: myoma, fibromyoma, epithelial, connective tissue tumor.