Boxplot representation of MMP2 and CHOP (E, G) expression in human breast tumors with low (IGF-1R z-score < − 1) versus high (IGF-1R z-score > 1) IGF-1R expression (Student’s t test, MMP2, P < 6.864 × 10− 10; CHOP, P < 3.172 × 10− 10). This evidence concerns the gene DDIT3 and breast neoplasm.