Alshaker and colleagues demonstrated that leptin as an adipokine was able to induce upregulation of SPHK1 and in turn SPHK1 could contribute to leptin-induced STAT3 activity in breast cancer via transactivation of IL-6/gp130 (Alshaker et al., 2014; Alshaker et al., 2015). Here, STAT3 is linked to breast carcinoma.