Detection of Human Endogenous Retrovirus Type K-Specific Transcripts in Testicular Parenchyma and Testicular Germ Cell Tumors of Adolescents and Adults

Testicular germ cell tumors (TGCTs) of adolescents and adults have been shown to contain proteins of the human endogenous retrovirus type K family. In a recent study, expression of these retroviral sequences was confirmed using in situhybridization, which also showed expression in carcinomain situ, the precursor of all TGCTs. Because of the clinical significance of a test for early diagnosis of TGCTs, we studied whether expression of human endogenous retrovirus type K genes could be an informative parameter. Therefore, we investigated TGCTs of various histologies and testicular parenchyma with and without carcinoma in situusing reverse transcription-polymerase chain reaction for expression of thegag, env, and prtgenes. The gagand prtgenes were expressed in all samples tested. The envtranscripts were not found in TGCTs showing somatic differentiation only but could be detected in most normal testicular parenchyma samples. Therefore, detection of human endogenous retrovirus type K transcripts cannot be used for early diagnosis of TGCTs. Simultaneous expression of multiplegagsequences was found both in normal parenchyma and TGCTs, and we demonstrated that expression of gagsequences with an extra G, necessary to generate a functional protein, was not limited to TGCTs.