The word cancer is a very broad term that covers more than 200 types of diseases. Each of these types of diseases can have completely different characteristics from the rest of the cancers and can be considered as independent diseases, with their causes, their evolution, and their specific treatment.
How do the cells and tissues of our body behave?
The body comprises of millions and trillions of cells. As the use, aging and/or tissue damage occur, the cells that compose it multiply, replacing aging or dead cells, in order to maintain the integrity and proper functioning of the different organs. In the multiplication of a cell, it duplicates all its components, to then divide; originating two cells exactly the same as the original, both in structure and function.
Cell multiplication and division occurs at a certain rate for each tissue: this is how the covering tissues (skin, epithelium of the digestive system), which require rapid turnover, have a high rate of cell multiplication, unlike other tissues such as the nervous system, whose cells have almost no multiplication. Another important feature of normal cells is that they are specialized to be part of a specific tissue and fulfill a certain function: this feature is called differentiation. Thus, normally a cell that is part of a tissue is not found in another, muscle cells are formed and grow in the muscles and not in the bones; those of the kidneys do not grow in the lungs, etc.
This is because the cells, in addition to the specific function they acquire in a given tissue, have molecules on their surface, which allows them to be linked to cells of that tissue and not another. Cancer arises when normal cells become cancerous, that is, they acquire the ability to multiply uncontrollably and invade tissues and other organs.
This process is called carcinogenesis.
Carcinogenesis lasts for years and goes through different phases. The substances responsible for producing this transformation are called carcinogens. An example of these is ultraviolet radiation from the sun, asbestos or human papillomavirus.
The first phase begins when these agents act on the cell by altering its genetic material (mutation). A first mutation is not enough to cause cancer, but it is the beginning of the process. The indispensable condition is that the altered cell is able to divide. As a result, damaged cells begin to multiply at a slightly higher rate than normal, transmitting to their descendants the mutation. This is called the tumour initiation phase and the cells involved in this phase are called initiated cells. The alteration produced is irreversible, but insufficient to develop cancer.
If the carcinogenic agents act repeatedly and repeatedly on the cells, the cellular multiplication begins to be faster and the probability of new mutations occurring increases. This is called the promotion phase and the cells involved in this phase are called promoted cells. We currently know many factors that act on this phase, such as smoking, inadequate nutrition, alcohol, etc.
Finally, the cells initiated and promoted undergo new mutations. They become increasingly anomalous in their growth and behavior. They acquire the capacity for invasion, both locally infiltrating the surrounding tissues, as well as from a distance, causing metastasis. It is the progression phase. If you are a cardiologist and you would like to get exposure and get your clinic registered visit private company registration portal.
As a result, the cells are increased in number, have alterations in shape, size and function and have the ability to invade other parts of the body.