CTLA4 and colon carcinoma: Preclinical studies on breast and colon carcinoma showed that three fractions of 8 Gy or five fractions of 6 Gy on consecutive days (in combination to CTLA-4 blockade) were superior at inducing abscopal effects than a single ablative dose of 20 Gy [26], demonstrating that time is critical when it comes to eliciting abscopal effects.