ABSTRACT
Cancer is the second cause of death in developed countries, and its incidence is steadily on the rise. In general, since 1930, cancer death rates have increased with age for both males and females, and the age-specifi c occurrence of cancer was similar for both genders (Wingo et al. 2003). Furthermore, the fi ve-year-mortality trends for the most relevant types of tumors have only slightly receded (only up to a 3.3% for prostate cancers) or even have increased (2.2% for liver cancer) in the last 40 years (Wingo et al. 2003, Marshall 2011), in spite of the enormous amounts of money invested in cancer research during this period. Most of the advances in the fi eld of cancer treatment have been related to the early detection programs that have increased our chances of identifying cancers in very early stages (Etzioni et al. 2003). However, given the disseminated nature of the disease (Husemann et al. 2008, Sanchez-Garcia 2009), in many cases this early detection comes already too late, and the prognosis for metastatic cancers is today as dark as it was 50 years ago.
