1. Epidemiology and Biostatistics Unit, Istituto Nazionale Tumori IRCCS Fondazione G. Pascale, I‑80131 Naples, Italy
2. Department of Biomedical and Biotechnological Sciences, University of Catania, I‑95123 Catania, Italy
3. Laboratory of Clinical Virology, School of Medicine, University of Crete, 71003 Heraklion, Greece