Cancer emerges when the genes of a somatic cell mutate and transform this cell and daughter cells into malignant cells. This kind of cells is characterized by an abnormal cell growth that ignores stop signals of neighboring cells and the body. As a results, a malignant cell clone forms, which replaces or damages healthy cells, tissue and organs and also deprives them of nutrients. The malignant cells do also invade other parts of the body where they do not belong and often spread throughout the whole body, using the blood and lymphatic system at a later stage (metastases).
The most frequent types of cancer are bowel cancer, breast cancer, lung cancer and prostate cancer. Malignant tumors can generally arise out of any kind of cell and organ of the body. But the degree of severity can vary enormously. Some cancer diseases can cause death quickly if not treated, whereas others do merely grow within several years without therapy.
Malignant tumors/cancer include carcinoma, sarcoma, tumors of the nervous system, malignant melanoma and diseases of the blood and lymphatic system like leukemia, lymphoma, multiple myeloma, myeloproliferative diseases and myelodysplastic syndromes.