Abstract
In this chapter, cancer is discussed as the second leading cause of death that globally kills nearly 10 million people every year. In this context, we will have to realize, that one in two of us will be diagnosed with cancer at some point of his/her life. Malignant tumors can arise from different tissues and organs, thus there are many different types of cancer. In all of them the normal control of cell division is lost, so that an individual cell multiplies inappropriately forming a primary malignant tumor. The cancer cells may eventually spread through the body and form potentially deadly metastases. The most promising strategy for reducing both, the number of cancer cases as well as their mortality, are preventive interventions like eliminating exposure to carcinogens, such as tobacco smoke.