Therapies targeting PD-1, PD-L1, or CTLA-4 are therefore promising strategies to enhance CTL-mediated anti-tumor efficacy (Gravitz, 2013; Gubin et al, 2014; Herbst et al, 2014; Powles et al, 2014; Tumeh et al, 2014). This evidence concerns the gene CTLA4 and neoplasm.