1. Department of Social Medicine; Faculty of Medicine; University of Crete; Heraklion Greece
2. Molecular Diagnostics of Oncogenic Infections Department; Infection and Cancer Programme; German Cancer Research Center (DKFZ); Heidelberg Germany
3. Department of Pediatric Hematology-Oncology; University Hospital of Heraklion; Heraklion Greece
4. Instituto de Salud Global Barcelona Barcelona; Catalunya Spain
5. Hospital del Mar Medical Research Institute (IMIM); Barcelona Spain
6. Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP); Madrid Spain
7. Cancer Epidemiology Research Programme; Catalan Institute of Oncology; L'Institut d'Investigació Biomèdica de Bellvitge (IDIBELL); Barcelona Spain