1Department of Medical Epidemiology, Karolinska Institutet, Stockholm, Sweden
2Department of Medicine, Channing Laboratory,Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
3Department of Surgery and Centre for Clinical Research, Uppsala University, Central Hospital, Västerås, Sweden
4Regional Oncologic Centre, Uppsala, Sweden
Copyright © 2001 Cancer Research Campaign
This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material.If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit https://creativecommons.org/licenses/by/4.0/.