Wilms' Tumor 1(WT1) is a tumor suppressor gene, which is related to nephroblastoma. At the same time, it can be used to mark malignant mesothelioma and ovarian serous tumor, while uterine serous cancer is negative. Ewing's sarcoma and primitive neuroectodermal tumor are also negative, Wilms' Tumor 1(WT1) can be used for differential judging of some small round cell tumors.