QRT-PCR assay showed the expression level of SALL4 in dysgerminomas, yolk sac tumors, mixed ovarian germ cell tumors, and immature teratoma to be pronounced 20.39 times, 30.17 times, 42.34 times and 11.6 times higher than normal ovarian specimens, successively (Figure 1D,E). This evidence concerns the gene SALL4 and yolk sac tumor.