Interestingly, MRD− childhood BCP-ALL patients (discovery plus validation cohorts) who presented with >32% EC within BM stromal cells at day +78 had a significant shortened median DFS than those patients that showed lower EC numbers (≤32% EC among all BM stromal cells) with median 5-year DFS rates of 64.1% vs. 80.7%, respectively (p = 0.02) (Supplementary Figure S2). This evidence concerns the gene OPN1SW and acute lymphoblastic leukemia.