Through evolution, organisms were influenced by a variety of harmful agents, and in order to survive, they have developed various defense mechanisms from these effects. They have developed mechanisms ranging from DNA repair to destroy its own cells if they harm one. Scientists have recognized the positive aspects of these mechanisms and today they are still being examined to improve the quality of life. Because of the industry and ways of life, people are influenced by everyday more and more harmful agents, and reckless behavior like drug use problems, poor diet and smoking, gives your body extra stress. Because of this way of life many people today have resulted in tumors, of which the most common are cancers. The research function of tumor and normal cells, results with different methods which can be used as ways to prevent disease, or at least reduce their impact. Methods for assessing genotoxicity are a good indicator of DNA damage and DNA repair capabilities over time. These methods can be used in monitoring the protective effects of some natural or synthetic compounds on cells from the consequences of genotoxic damage.They have already a big success in the field of cancer chemoprevention, but have not yet found a way to completely eradicate the disease. Continuing research, every day we are getting closer and closer to a better quality of life, and that is why such research should be encouraged.