CTLA4 and melanoma: Patients with high tumor CTLA-4 expression in mesothelioma, nasopharyngeal carcinoma and melanoma had a poorer prognosis than those with low expression, which suggested CTLA-4 as a potential target for tumor immunotherapy (Salvi et al., 2012; Huang et al., 2016; Roncella et al., 2016).