Given the latest advances in cancer research, which includes basic research and its derived diagnostic, clinical, and therapeutic applications, the book New Trends in Cancer for the 21^st Century is written by individuals such as molecular biologists, whose tasks are to decipher, after sequencing the human genome, those new genes and pathways involved in the carcinogenesis process; clinical and molecular pathologists, who apply these discoveries for the molecular diagnosis and characterization of the tumor; and clinical oncologists, who treat patients. Pharmacogenetics introduces new perspectives in the translational fields with the design of drugs against specific targets, which at this moment are in clinical trials phases. This book achieves a state of the art in every field of cancer research and discusses the new perspectives that will open the future for cancer treatment (basic research, new technologies, new drugs, therapies...). For this reason, the book is intended for pathologists, clinicians, and biologists, as well as fellows and students of physiology and medicine.