1. Institute of Clinical and Preventive Medicine
2. Faculty of Medicine, University of Latvia, Riga, Latvia
3. International Agency for Research on Cancer (IARC/WHO), Early Detection, Prevention and Infections Branch, Lyon, France
4. Agencia Costarricense de Investigaciones Biomédicas, Fundación INCIENSA, Costa Rica
5. Hospital Universitario San Ignacio, Bogota, Columbia