In xenograft tumors, Ki-67 and PCNA, the most commonly used markers of tumor cell proliferation, were downregulated after intravenous administration of mogroside V. Terminal deoxynucleotidyl transferase dUTP nick end labeling assays showed that mogroside V treatment promoted apoptosis of pancreatic cancer cells in the xenograft tumors. The gene discussed is PCNA; the disease is neoplasm.