SALL4 and yolk sac tumor: Nonetheless, SALL4 expression is reported in numerous malignancies, such as breast and lung cancers [14,15], precursor B-cell lymphoblastic lymphoma [16], myelodysplastic syndromes (MDS) [11], acute myeloid leukemia (AML) [10,11], endometriotic samples [17], ovarian germ cell tumors [18], all types of testicular germ cell tumors (GCTs) [19], all metastatic seminomas/dysgerminomas and embryonal carcinomas [20], and primary mediastinal yolk sac tumors (YSTs) [21].