IMMUNOHISTOCHEMICAL MARKERS OF CARCINOMA INSITU OF THE TESTIS ALSO EXPRESSED IN NORMAL INFANTILE GERM-CELLS

Carcinoma in situ of the testis is an intratubular, pre-invasive lesio n preceding germ cell tumour. In adult men, carcinoma in situ cells di ffer in several aspects from normal germ cells. For example, placental -like alkaline phosphatase and/or the epitopes for the monoclonal anti bodies M2A, 43-9F and TRA-1-60 are not seen in normal germ cells, wher eas their presence is considered a specific sign of carcinoma in situ. As it is known that placental-like alkaline phosphatase and the epito pe for TRA-1-60 are expressed in normal fetal germ cells it is possibl e that the markers could appear in normal infantile germ cells in a pe riod after birth before they lose their expression. In children, carci noma in situ cells may be difficult to identify morphologically and th e use of the markers could be of great value. However, little informat ion is available on the expression of the markers of adult carcinoma i n situ in normal infantile germ cells. We investigated gonads from 66 boys less than 15 years old who died suddenly. Their deaths were unrel ated to testicular disease. Immunohistochemical staining with anti-pla cental-like alkaline phosphatase antibody and monoclonal antibodies TR A-1-60 and 43-9F were performed. We found that these markers were expr essed in some normal infantile germ cells until the age of 1 year. The refore, these markers are not suitable for diagnosis of carcinoma in s itu during the early postnatal period of life. Furthermore, our findin gs of placental-like alkaline phosphatase and the epitope for TRA-1-60 in normal germ cells.before birth indicate that the markers of adult carcinoma in situ cells are of embryonic origin. This is in accordance with the hypothesis that carcinoma in situ cells are fetal germ cells malignantly transformed during fetal life, although re-expression of the antigens could provide an alternative explanation.