RUNX1 and breast cancer: The luminal B signature included mutations in TP53, RB1, RUNX1 and MALAT1 (a non-coding RNA) and was associated with poor outcome features, such as high baseline and surgical Ki67 levels (a proliferation marker), high grade histology and high PEPI scores (preoperative endocrine prognostic index-predicts the risk of breast cancer coming back in women who got hormonal therapy before surgery).