We addressed that question by expression of activated IL7RA (IL7RAins) in human hematopoietic cells and showed that expression of activated IL7RA (IL7RAins), with or without CRLF2, modify human B-cell development into a state that could evolve into an overt “Ph-like” BCP-ALL. The gene discussed is CRLF2; the disease is acute lymphoblastic leukemia.