In ER+ breast cancer, on the one hand, calycosin inhibits the metastasis and invasion of cancer cells in the human breast cancer cell lines T47D and MCF-7 within the concentration range of 100–400 μM by suppressing the basic leucine zipper ATF-like transcription factor (BATF)/transforming growth factor β1 (TGFβ1) signaling pathway, helping to inhibit cancer cells’ epithelial–mesenchymal transition (EMT), in the context of which BATF facilitates cell migration and invasion by increasing TGFβ1 expression [180]. The gene discussed is TGFB1; the disease is cancer.