Cancer is a DNA disease in which the early stage is represented by the inactivation of suppressor genes and activation of oncogenes, which result in transformed cells that grow out of biological control. Tumor progression is locally favored by mitogenic effects of hormones, or growth factors that stimulate the tumor's growth, or by inducing angiogenesis. The book contains chapters written by experts in the topic, and exhibits current developments in the methodology of cell and molecular biology, which have deeply advanced the understanding of cancer's prevention and prognosis. We hope that it will be helpful for physicians, researchers, and students in life sciences, and will stimulate discussion and research for new therapeutic approaches against cancer.