CTLA4 and melanoma: Overexpression of miR-222-3p was found to enhance the resistance of tumor cells to tumor infiltrating lymphocytes (TILs) by down-regulating the expression of intercellular cell adhesion molecule-1 (ICAM1) in melanoma, which resulted in ipilimumab (anti-cytotoxic T lymphocyte-associated antigen-4 antibody) resistance in patients with melanoma (28).