These classical signaling pathways were also reported in BCSCs-related BC metastatic organotropism, which deserved close attentions, including the miR-31-Dkk1-Wnt/β-catenin axis, the BCL11A-Wnt/β-catenin axis, the LGR4-Wnt/β-catenin axis in BC lung metastasis, the Vismodegib&Sonidegib-SMO-GLI1/tGLI1 axis in BC liver metastasis and the MSC-derived EVs-Wnt/β-catenin axis, the hypoxia-Jagged2-Notch axis in BC bone metastasis. The gene discussed is SMO; the disease is breast cancer.