Previous study showed that 5 mM and 10 mM SP can significantly reduce the cell viability of ER-negative BC cell line JIMT-1 and ER-positive BC cell line MCF-7 under 1, 2, or 3 days treatment and the anticancer mechanism was mediated by decreased proliferating cell nuclear antigen and cell cycle arrest [31]. The gene discussed is PCNA; the disease is breast cancer.