The utility of CDX2, GATA3, and DOG1 in the diagnosis of testicular neoplasms: an immunohistochemical study of 109 cases.

We identified 109 testicular tumors, including pure and mixed germ cell tumors and sex cord-stromal tumors, and conducted immunohistochemical staining for CDX2, DOG1, and GATA3 to address the potential utility of these readily available and commonly used markers in the evaluation of testicular tumors. Their expression has not been previously thoroughly examined in testicular germ cell tumors. The distribution, percentage, and intensity of positivity were assessed. CDX2 was positive in all yolk sac tumors, 25% of choriocarcinomas, 9% of seminomas, and 4% of embryonal carcinomas (sensitivity for yolk sac tumor, 100%; specificity, 89% [teratomas excluded]). CDX2 also stained glandular components within teratomas and identified inconspicuous yolk sac tumor components in 3 cases previously diagnosed as pure embryonal carcinoma. GATA3 was positive in all choriocarcinomas (sensitivity, 100%). Weak GATA3 immunostaining was also seen in 12% of yolk sac tumors and 2 of 2 primitive neuroectodermal tumors. DOG1 was negative in all tumors, but stained spermatocytes and spermatids and the luminal borders of the epididymis and rete testis of nonneoplastic testis. We conclude that CDX2 is a sensitive and relatively specific marker for yolk sac tumor among the nonteratomatous germ cell tumors. It may serve to screen for yolk sac tumor components often overlooked on hematoxylin and eosin-stained slides. GATA3 is helpful in the recognition of trophoblastic cells, especially of intermediate type. DOG1 is a sensitive marker for spermatocytes and needs to be further studied for its significance.