Causes cancer / malignant tumors
Genetic mutations, which are the mainspring of tumor development, are caused by external factors in some patients. There is a number of known hazardous influences and mechanisms that can increase the risk of cancer, e.g.,
- smoking
- some viruses
- being exposed to certain chemicals (especially chemotherapy of previous cancer) or asbestos
- being exposed to ionizing radiation (radiation therapy)
- immunosuppressive drugs (because the immune system can suppress some tumors itself at an early stage)
Besides, there are specific genetic traits, increasing the risk of cancer. An important example is the mutation of a gene called BRCA, facilitating breast cancer significantly. A mutation of BRCA blocks mechanisms that could repair possible cancer-inducing mutations.
Non-cancerous diseases can also boost the risk of cancer like cirrhosis (liver cancer) or adenomas (benign tumors of the large intestine, bowel cancer).
It is essential to keep in mind that the existence of a tumor is not proven by risk factors associated with a malignant tumor, but that those risk factors only increase the likeliness of tumor growth. For example, in very few smokers, lung cancer is not caused by smoking.
The causes of cancer development are often uncertain, which might appear like fate or bad luck. Questions like “Why am I suffering from cancer?” or “What have I done wrong in my life?” are natural reactions. However, those questions are not crucial for planning the optimal therapy in most cases, even if one risk factor applies. It is imperative not to look back but forward. But finding a genetic risk factor can greatly influence disease prevention, and further examinations of family members may be advised.