JAK2 and precursor B-cell acute lymphoblastic leukemia: As further support, a more recent study using transgenic mice demonstrated that while expression of CRLF2 alone in B-lineage hematopoietic cells did not induce B-ALL development, CRLF2 transgenic mice transplanted with fetal liver cells expressing JAK2 p. R683G or JAK2 p. P933R-mutant JAK2 succumbed to ALL disease within 10–20 days post-transplantation (Kim et al., 2018).