SIK2 and breast cancer: Similarly, salt-inducible kinase 2 (SIK2) is capable of regulating the stem cell phenotype of breast cancer by favoring the phosphorylation of the CK1 protein kinase and the co-receptor of the Wnt/LRP6 signaling, facilitating the Wnt/β-catenin activation (Rong et al., 2022).