To determine that the advantage of these xenografts is related to cell apoptosis, we detected the expression of cleaved-caspase 3 through immunohistochemistry in the xenograft tumors, and the results were consistent with previous in vitro findings, suggesting that tumor with SUMO-defective HK2 was inversely associated with cell apoptosis and death. The gene discussed is HK2; the disease is neoplasm.