CRLF2 and acute lymphoblastic leukemia: Flow cytometric immunophenotyping for increased surface expression of TSLPR (encoded by CRLF2) is a highly cost-effective and predictive assay for detecting rearrangement of CRLF2 (both IGH-CRLF2 and P2RY8-CRLF2) and CRLF2 F232C missense mutation in primary ALL blasts [28], and is becoming routinely incorporated into diagnostic panels.