Consistent with clinical findings, studies have demonstrated that targeting SPHK1 using RNAi-mediated approaches or pharmacological SPHK1 inhibitors can reduce cell proliferation, induce apoptosis, synergize chemo- and endocrine sensitivity, impede invasion, and decrease metastasis in breast cancer (Antoon et al., 2011; Datta et al., 2014; Sukocheva and Wadham, 2014; Wang et al., 2018; Acharya et al., 2019). Here, SPHK1 is linked to breast cancer.