CTLA4 and neoplasm: Positive CTLA-4 expression was revealed in the tumor microenvironment in 86% of patients; it had low expression in TILs but a strong correlation between its positive expression and poor OS (p = 0.018) and between its negative expression and the high grading and diffuse type malignant cell occupation (p = 0.012 and p = 0.006, resp).