Phenotypically, we observed considerable differences in the distribution of distinct HSPC subsets in JMML vs. HD UCBs (Figure S3) with significantly higher hematopoietic stem cells (HSCs), CD34+ CD38− CD45RA+ CD90+ (Leukemic-MPP, Figure S3B), and CD34+ CD38+ CD45RA+ CD90+ (Figure S3C) subsets. This evidence concerns the gene CD38 and juvenile myelomonocytic leukemia.