To observe the in vivo tumor-prevention effect of T7-OCT4 vaccine, BALB/c mice were immunized with PBS, T7, OCT4, T7 + OCT4 (mixture of T7 and OCT4), or T7-OCT4 conjugate three times at biweekly intervals (On Day1, 14, 28). The gene discussed is POU5F1; the disease is neoplasm.