Colorectal cancers are the third most frequent cancer worldwide, with increasing incidence in the developing world. More positively, they provide a vivid example of how serendipity and clinical observation can lead to fundamental biomedical insights. Long-term use of nonsteroidal anti-inflammatory drugs was serendipitously found to reduce colorectal cancer incidence in large clinical trials. By taking these clinical results back into the lab, researchers identified an enzyme, cyclooxygenase 2 (COX-2), that is overproduced in colorectal cancers and is clearly involved in tumour development. Selective COX-2 inhibitors reduce the number of polyps in people with familial adenomatous polyposis, an inherited predisposition to colorectal cancer, so may be of significant clinical benefit in preventing colorectal cancer in these individuals.

This synergy of disciplines, not to mention the vast flow of information that cancer specialists have to battle with, highlights a prime motivation of one of two Nature review journals being launched on 1 October. Nature Reviews Cancer aims to help all cancer researchers not only to develop an overview of their own areas of expertise but also to understand new opportunities emerging in others.

Interdisciplinary motivations have also stimulated the launch of Nature Reviews Immunology. Immunology is a diverse and growing discipline, but it is also at risk of fragmentation. It faces major challenges. The threat from autoimmune diseases is ever-increasing; we do not yet know how to stimulate the immune system to combat cancer; infectious diseases are on the rise and the need for efficacious vaccines is ever-present; and much remains to be learned about overcoming organ-specific transplant rejection. And the statistics speak for themselves: 30% of all deaths in 2000 were attributable to infectious diseases, and 2.7 million people alone died from HIV infection.

Immunologists and cancer researchers clearly have a lot of work to do. The new journals are intended to help them and their disciplines thrive.