SPHK2 and leukemia: Alternately, SphK2 is significantly elevated in a broad range of human cancers, including bladder, melanoma, breast, neuroblastoma and leukemia (Neubauer et al., 2016; Bruno et al., 2020); in agreement to SphK2 expression in cancer, SphK2 down-regulation has been demonstrated to decrease the proliferation of cancer cells (Van Brocklyn et al., 2005; Hait et al., 2005), and SphK2-deficient xenografts show a significantly delayed growth (Weigert et al., 2009), pointing at a crucial role of the kinase in carcinogenesis.