Malignant tumor originate from cells that have transformed into cancercells - a process that we still do not fully understand. Cancer cells no longer perform the functions that are characteristic of the tissue from which they have developed. Malignant tumors usually grow rapidly. They often consist of undifferentiated tissues with irregular cell structure and infiltrate and destroy their environment through diffuse growth. They also have the ability to settle in other parts of the body (metastasis). The uninhibited spread of malignant tumours usually leads to pathogenic side effects and sooner or later to death.