Preface Tumor development and progression occur as a result of cumulative acquisition of genetic alterations affecting oncogenes and tumor suppressor genes. As a consequence of these alterations the arising tumor gains some fatal properties such as increased cell proliferation and decreased apoptosis, resulting in a net accumulation of tra- formed cells. Once a critical volume is achieved, lack of oxygen and nutrients limits further growth. To overcome this obstacle, the tumor cells initiate a program focused on the formation of new blood vessels within the host tissue. This process is termed...