CD19 and acute lymphoblastic leukemia: In other studies involving ETV6/RUNX1 B cell precursor ALL, Boiers and colleagues [186] identified human fetal liver CD19-IL-7R+/CD127+ (Lin-CD19-CD34+CD38+CD45RA+IL-7R+KIT+) cells, which during ontogeny (CS17 to CS20), transition from a myeloid-primed to a lymphoid-primed program, as the earliest human B lymphoid progenitors.