INTRODUCTION Celebrating an Anniversary In this issue of Science, we commemorate the 40th anniversary of the U.S National Cancer Act, which provided a massive stimulus for cancer research At the start of this "Cancer Crusade, researchers were already tackling some tough gus ions as refected in papers published bey scie ie in 1 7 l mong Cancer Crusade H)2时at40 tumor cells as foreign invaders that must be eliminated from the body? Do viruses play a role in human cancer? Skeptics might argue that 40 years later, cancer researchers continue to grap- CONTENTS ple with the same questions. Perhaps theres some truth in this. But our hope is News that the selection of articles in this special section of Science will explain wby1540Cancer Research and the s90 Billion Metaphor contemporary cancer research is providing a clearer view of the biology that will U.S. Cancer Trends lead to answers. Stratton(p 1553)discusses international efforts to sequence Combining Targeted Drugs the complete genomes of a wide range of human tumor types and the impact that this sequence information is anticipated to have on our understanding of to Stop Resistant Tumors working model for cancer cell metastasis is presented by Chaffer and Weinberg 1548 A Push to Fight Cance (p. 1559), who highlight the important role of cancer stem cells and a develop. in the Developing World mental process called the epithelial-mesenchymal transition. Schreiber et al.(p. 1551 Brothers in Arms Against Cancer 1565)describe "cancer immunoediting, a conceptual framework that integrates the immune systems dual roles in inhibiting and promoting cancer growth Reviews News reports examine other significant challenges for the field: Jocelyn 1553 Exploring the Genomes of Kaiser (p 1542)describes how even the best new drugs eventually seem to fail Cancer Cells: Progress and Promise and how they might be made more effective, David Malakoff(p. 1545)outlines a M. R. Stratton key social issue: the fast-rising cost of care. Martin Enserink(p 1548)reports on 1559 A Perspective on Cancer efforts to close the huge disparity between cancer treatment in rich and develop- Cell Metastasi ing countries And Mitch Leslie (p. 155 1)describes how researchers are taking C L Chaffer and R A Weinberg a new look at the role of p53 and the related proteins p63 and p73 in tumors 1565 Cancer Immunoediting AvideoreportbyRobertFrederickappearsonlineatwww.sciencemag Integrating Immunity's Roles in org/special/cancer2011/, along with links to additional reading material Cancer Suppression and Promotion4