Corrigendum: Association of CTLA-4 Gene Variants with Response to Therapy and Long-term Survival in Metastatic Melanoma Patients Treated with Ipilimumab: An Italian Melanoma Intergroup Study - Queirolo, Paola; Dozin, Beatrice; Morabito, Anna; Banelli, Barbara; Piccioli, Patrizia; Fava, Cristiana; Leo, Claudio; Carosio, Roberta; Laurent, Stefania; Fontana, Vincenzo; Ferrucci, Pier Francesco; Martinoli, Chiara; et al. (Frontiers in Immunology, 2018)