Most diseases are called multifactorial because many factors act together to trigger them. Cancer is not an exception to the rule. Thus, tobacco is a cancer factor, it is carcinogenic, but not all smokers develop cancer, because other factors intervene, such as alcohol.
To see who does cancer affect, we can classify the factors into 6 main groups: -Age; -Genetic heritage; -Immune System; -Diet; -Environment; -Viruses. Age: as the human age grows in time, cells suffer alterations, namely they change their structure, in a genetic or carcinogenic fashion, and sometimes this can cause cancer.
Genetic heritage: for a cell to become cancerous, it must undergo a number of genetic mutations. If it happens that these mutations were there from birth, then this is a genetic cause. It is genetic predisposition. However, people are not all cancer prone and most cancers occur without genetic predisposition.
The immune system: it defends the body from harmful agents and foreign infiltrations: germs, viruses, cancer cells, organ transplants, etc. People whose immunity decreases are exposed to certain types of cancer.They are:
-Patients who have had a transplant: to avoid rejection, they are prescribed drugs that bypass the immune system.
-Patients who suffer from certain rare or genetic diseases, which have an impact on the immune system.
These people are mainly affected by two types of cancer: -The cancer of viral origin - cervical cancer, for example; -Lymphoma, developed from the lymphocytes, which are themselves part of the immune system
Diet: An estimated one in three cancer cases are related to errors in nutrition. In the West, people are eating too much animal fat, not enough fruits and vegetables. But there are still too many unknowns here to draw a clear conclusion.
About 15 years ago, coffee was accused of being a carcinogen for the pancreas and bladder. Today we know that's not true. Food additives are often blamed but their quantity is, however, often too small to be a threat. No doubt, to avoid the accumulation of toxins in the body, nutritionists recommend diets as varied as possible.
Environment. This includes tobacco smoke, sun, natural or man-made radiation, asbestos, pollution at the workplace, such as the one faced by miners.
Viruses. The types of cancers caused by viruses are not contagious. Viruses act in a manner that allows for genetic mutations and they cause chronic inflammation and train. For example, there is a connection between cervical cancer and the HPV virus, between liver cancer and hepatitis B and C. Viruses do nothing but increase the risk. Not all infected people get sick with cancer. We also need to not that cirrhosis, especially those caused by the abusive consumption of alcohol, can easily degenerate into cancer.