CTLA4 and carcinoma: In a seminal study of 2 preclinical mouse carcinoma models, evaluation of RT (20 Gy X 1, 8 Gy X 3, or 6 Gy X 5 fractions over consecutive days) in combination with an anti-CTLA-4 antibody determined that fractionated RT but not single-dose RT achieved significantly enhanced tumor responses both within and outside the radiation field (abscopal effects) when combined with CTLA-4 blockade [55].