The combination of two fractions of IR with anti-CTLA4 yielded a favorable trend in tumor growth delay compared to two-fraction IR with IgG, although it was not statistically significant (median days to endpoint: 13.5 Gy × 2 + anti-CTLA4 44 days, 13.5 Gy × 2 + IgG 41.5 days; Figure 4d). This evidence concerns the gene CTLA4 and neoplasm.