Biology question....please help! I'm confused....Easy 10 points?

Well, think about it. If radioactive isotopes can be incorporated into the cell, that means the radiation from the isotopes is there to stay. And as we all know, radiation is bad. If you start getting more and more radioactive isotopes in your cells, you start getting more and more radiation. Radiation can damage other cell components and mess with RNA and DNA... hello, cancer!