After decades of research into the biology of cancer, it is good to finally see some signs of a therapeutic pay-off (see page 470). But the statistics of cancer mortality still make depressing reading. All the more so given that, in major Western countries, tobacco plays a part in one-third of cancer deaths — mainly, but not exclusively, through lung cancer.

This vast toll underlines the continued importance of prevention — and especially of campaigns to reduce smoking — in the war on cancer. Stopping the relentless promotional activities of tobacco companies would be a major step forward.

But our imperfect world is home to conflicting political and economic forces. In Europe, for example, the European Commission gained some responsibility for public health with the 1993 Maastricht Treaty, and has an active anti-smoking policy. Yet the European Union spends around 1 billion euros (US$900 million) each year subsidizing tobacco farmers, three-quarters of whom are in Italy and Greece; Spanish and French farmers receive most of the remaining subsidies. In total, the handouts are broadly comparable to the amount spent annually on cancer research in Europe's public sector. The European Commission wants to phase out the subsidies, which have their historical roots in the European Union's outmoded Common Agricultural Policy, but is facing resistance from some of the member states that benefit.

Researchers are not above these messy conflicts. A proposed European Union directive to restrict tobacco advertising is now being hotly debated, while scientists continue to accept the patronage of Philip Morris, the world's largest tobacco company, which awards a prestigious and generous research prize in Germany every year (see Nature 410, 725; 2001).

Given the centrality of the war on cancer to public health, we should all be asked: which side are you on?