HUMAN ENDOGENOUS RETROVIRUS (HERV)-K TRANSCRIPTS IN GERM-CELL AND TROPHOBLASTIC TUMORS

Prompted by the observation of retroviral particle formation in terato carcinoma cell lines and the consistent finding of antibodies against Gag and Env proteins encoded by human endogenous retrovirus (HERV)-K g enomes in the sera of patients with classical seminoma, we studied ova rian and testicular germ cell tumours, their precursor lesions, dysgen etic gonads, and trophoblast lesions for expression of HERV-K sequence s by in situ hybridization using radioactive and non-radioactive probe s. HERV-K transcripts were detected in all testicular and ovarian germ cell tumours with the exception of teratomas and spermatocytic semino mas. HERV-K expression was also common to testicular carcinoma in situ as well as gonocytes of dysgenetic gonads. Among gestational trophobl astic lesions, HERV-K expression was regularly found in choriocarcinom as, but not in molar lesions. The patterns of HERV-K expression sugges t a common molecular pathogenesis of most germ cell tumour entities an d malignant gestational trophoblastic disease. They furthermore suppor t the concept of carcinoma in situ as a precursor lesion common to mos t testicular germ cell neoplasms. The detection of HERV-K gene product s in body fluids and tissues may aid diagnosis and monitoring of germ cell tumours and related lesions.