CD4 and acute lymphoblastic leukemia: ETP-ALL have a distinctive gene expression signature characterized by high levels of expression of myeloid markers, i.e., LYL1, LMO2, CD34, CCND2, KIT, GATA2, and CEBPA, and low levels of expression of genes related to thymocyte differentiation, such as CD1, CD4, CD8, TCF7, and LEF1 [5,6,24].