JAK2 and acute lymphoblastic leukemia: Over 30 different JAK2 fusion partner genes have been identified in Ph-like ALL to date, the most common of which is PAX5 (Paired box 5) (28.7%) (Table 3, Supplementary Table S1) (Roberts et al., 2012; Roberts et al., 2014a; Yano et al., 2015; Imamura et al., 2016; Roberts K. G. et al., 2017; Boer et al., 2017; Reshmi et al., 2017; Li et al., 2018; Schwab and Harrison, 2018; Gu et al., 2019; Tang et al., 2019).