DOG1 has been shown to be sensitive and specific when detecting GISTs, although expression of DOG1 in other mesenchymal tumors, such as Ewing's sarcoma, angiosarcoma, leiomyosarcoma, and synovial sarcoma, has also been reported; there have also been occasional cases of DOG1 expression in malignant melanoma and germ cell tumors [1, 7–10]. The gene discussed is ANO1; the disease is germ cell tumor.