However, Weigert et al. and Scheartzman et al. demonstrated limited in vitro efficacy of ruxolitinib in human BCP-ALL CRLF2 rearranged (r)/JAK2 mutated cell lines [19-21], suggesting that other pathways may be involved in TSLPR signaling and that treatment with ruxolitinib alone may not be sufficient for hiCRLF2 patients, as also recently described by Tasian et al. [22]. Here, JAK2 is linked to acute lymphoblastic leukemia.