CRLF2 Gene in B-cell Acute Lymphoblastic Leukemia

B-cell acute lymphoblastic leukemia (B-ALL) is a subset of ALL that comprises 75% of ALL cases. There are a variety of chromosome aneuploidy or chromosomal rearrangements implicated in B-ALL. Deregulation of CRLF2 expression is seen in 5-15% of B-ALL patients and occurs primarily via a reciprocal translocation with immunoglobulin heavy chain (IGH), rearrangements of CRLF2, deletion within the PAR1 region of the X and Y chromosomes, and CRLF2 mutations as well as mutations of the CRLF2-involved pathways and are seen in Ph-like B-ALL. They are associated with a poor prognosis. Blinatumomab is an available immunotherapy, and there are currently a few ongoing clinical trials to treat CRLF2 B-ALL. This review focuses on the role of CRLF2 in B-ALL and summarizes the literature regarding its molecular pathways, clinical significance, incidence rates across demographics, therapies, and areas of further research.