IMMUNOHISTOCHEMICAL EXPRESSION OF EMBRYONAL MARKER TRA-1-60 IN CARCINOMA IN-SITU AND GERM-CELL TUMORS OF THE TESTIS

Background. Testicular cancer is preceded by the noninvasive stage of carcinoma in situ (CIS). According to a recent hypothesis, testicular CIA cells are germ cells transformed in fetal life. The idea of an emb ryonal origin of testicular germ cell neoplasia would be strengthened by the finding of antigenic similarity between fetal germ cells, CIS c ells, and invasive testicular germ cell tumors. Methods. Monoclonal an tibody (MoAb) TRA-1-60 raised against a human embryonal carcinoma cell line was immunohistochemically tested on 21 fetal gonads (11 male gon ads and 10 female gonads; 11th-24th week of gestation). In addition, T RA-1-60 was tested on tissue from 27 testes with CIS, 11 testes with i nvasive testicular cancer, and 24 adult and 4 infant testicular contro l specimens. Results. Expression of TRA-1-60 was found in germ cells o f six female and two male fetal gonads. In addition, 26 of 27 adult hu man testes with CIS, 7 of 8 seminomas, and 3 of 3 embryonal carcinomas were TRA-1-60 positive. Conclusions. The study demonstrated an antige nic link between fetal germ cells, cells of CIS and seminomas, and emb ryonal carcinomas. The results provided additional evidence for the hy pothesis that testicular neoplasia arises during early fetal life and CIS cells are malignant fetal gonocytes.