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 - Paola Queirolo; Beatrice Dozin; Anna Morabito; Barbara Banelli; Barbara Banelli; Patrizia Piccioli; Cristiana Fava; Claudio Leo; Roberta Carosio; Stefania Laurent; Vincenzo Fontana; Pier Francesco Ferrucci; et al. (Frontiers in Immunology, 2018)