Nowadays cancer kills thousands of humans around the world, so its research presents an important
challenge to decrease cancer mortality. Strategies for cancer research have made great advancement in the last
century, providing major insight into the complexity of tumor development. Numerous experimental protocols for
many years have been performed to mimic features of cancer cells in humans; for example, to generate tumors in
living organisms and study cancer in cultured cells. This chapter describes several of theses biological models: 1)
chemical carcinogenesis protocols 2) genetically modified animals (transgenic and knockout mice), 3) cancer cell
lines culture, 4) gene manipulation in cultured cells such as DNA transfection and RNA interference for gene
knockdown and 5) the concept of cancer stem cells. The significance of in vivo and in vitro models for cancer
research lies in the possibility of providing improved understanding of cancer biology and cancer treatment.
Keywords: Carcinogenesis, cell culture, transgenic mice, DNA damage, cancer stem cells, knockout mice, chemical
carcinogen, cytochrome p450, metabolic activation, DNA adducts, dysplasia, solid tumors, DNA transfection, gene
silencing, RNA interference.
