Physalin A inhibited proliferation and migration of breast cancer cells and mammospheres formation. In addition, physalin A inhibited the formation of breast cancer stem cells and decreased the transcript levels of BCSC-related genes (Oct4, CD44, Sox2, c-myc, and Nanog) via regulation of the Hedgehog/Hippo signaling pathway. The gene discussed is MYC; the disease is breast carcinoma.