Cancer is an umbrella term for a disease with a very diverse appearance: The ulcers, which are summarized under this name, affect virtually all organs of man. The lung is just as spared as the stomach and intestines, esophagus and skin, bones and brain, just to name a few examples.
A disease with many causes
Factors that cause cancer appear to be at least as diverse as the manifestations of the disease: it is now known that it is not simply an "old age disease, " although age plays a major role in its development.
Thus, cancer can also be triggered by environmental factors: sunlight promotes the development of skin cancer, and cigarette smoke produces lung cancer. On the other hand, for example, gynecologists occasionally warn their patients if they find a particular virus in the vaginal mucosa. This can also cause cancer, which is why the affected women regularly should come to check-ups.
Cancer can also be inherited
To make it even more complicated, cancer (or rather the tendency to get cancer) is sometimes hereditary: best known are hereditary breast cancer and hereditary colon cancer. In families who are burdened with this, there is an increased frequency of this disease.
Where does the name "cancer" come from?
By the way, the ancient Greeks gave the name to the disease. The ulcers that develop in breast cancer sometimes produce superficially visible jammed veins that have a faintly cancerous shape with their foothills. The Greek word for the sideways running shellfish, "karkinos", is also the root of the term carcinoma.
What happens when cancer develops?
First of all, a cancer is a new formation of the body's own tissue. It is therefore not a "raid" of a foreign pathogen that multiplies in the body (as is the case with bacterial infections). But how is it that something just "starts to re-form and grow" there?
In principle, a cell - at first it is actually only a single one - breaks out of the regulations of its tissue association in which it lives and performs its work and begins to divide. The fact that cells divide and multiply is not an uncommon occurrence, even in the mature body. Cells are constantly being formed here, as, for example, the skin, the mucous membranes of the gastrointestinal tract and the cells of the blood are constantly renewed.
Old cells are lost for this, they are shed (in the case of the skin) or destroy themselves in a process that scientists call apoptosis (Greek "falling foliage"), by itself. This ensures that a balance of new formation and destruction arises.
However, the proliferation that occurs during carcinogenesis is not the sensibly controlled growth necessary for the renewal of the tissue. Rather, the single cell breaks out of this control and multiplies, without having received the "permission" for this.
Cancer is a "genetic" disease
The cell is therefore multiplying "out of bounds" because the corset that she has put on, that is disciplining her and making her live in harmony with her neighbor cells, has been torn apart: she no longer recognizes the signals of her surroundings or misunderstand it. These signals, which tell the cell whether it is allowed to divide or not, form the basis for working in a multicellular organism "all for one", meaning that the multiplication of individual cells is meaningfully controlled for the entire organism.
The corset of a cell, which makes it a useful part of the whole organism, is its genome. It contains information about how the cell has to receive and interpret the signals of its environment. So if the genetic material changes, this interaction can also change.
The cell, which previously performed its service to the whole organism in the tissue association, becomes a "deserter" who, without asking whether that makes sense, increases himself. The emergence of cancer is therefore always preceded by a change in the genome, which is why the disease is also referred to by many scientists as a "genetic disease".
The change in genetic information, despite the diversity of the countless forms in which cancer occurs, is the common denominator of this disease. And that is also the key to understanding why cancer is caused by so many different factors.
Cancer - a disease of old age?
Looking at the incidence of cancerous tumors in relation to age, it appears that 60 percent of all new cases occur in people older than 60 years.
How can this be understood against the background that it is a "genetic disease"? Presumably, it is because the genetic material of human cells is very well protected from change. Because numerous systems, which are also called "guardians of the genetic material", constantly ensure that nothing happens to the "software of life". As a result, there are so few errors that it takes a long time for a change to actually occur, which then triggers cancer growth.