C4‐2‐cell xenograft tumor treated with MLT (200 mg/kg, intragastric administration) was significantly smaller with a reduced growth rate, and weight compared with tumors treated with a vehicle (EtOH), and C4‐2 tumor with stably knocked out CES1 expression showed an opposite pattern of tumor growth compared with that of the vector‐transduced tumor. Here, CES1 is linked to neoplasm.