LINE-1 retrotransposon expression in pediatric germ cell tumors.
BACKGROUND
Human LINE-1 (L1Hs) is a retrotransposon that is known to cause insertion mutations. Previous work demonstrated that at least 10% of adult testicular germ cell cancers expressed the L1Hs element.


METHODS
Pediatric germ cell tumors were assayed for L1Hs expression by in situ immunohistochemical methods using an antibody directed against one of the L1Hs-encoded proteins.


RESULTS
Approximately 10% of pediatric germ cell tumors express abundant amounts of the L1Hs protein. The element was expressed in 1 of 19 ovarian tumors, 1 of 20 testicular tumors, and 4 of 19 extragonadal tumors. The reactive cells in all cases appeared to be embryonal carcinoma or yolk sac tumor cells. None of 32 ovarian immature teratomas gave positive results, suggesting that more differentiated tissues do not express L1Hs abundantly.


CONCLUSIONS
It appears that neither the age nor sex of the patient, nor the location of the tumor, has a significant influence on the degree of L1Hs expression.
Department of Cellular Pathology, Armed Forces Institute of Pathology, Washington, DC 20306-6000.
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Fanning
D000293:Adolescent; D000328:Adult; D000906:Antibodies; D002648:Child; D002675:Child, Preschool; D004251:DNA Transposable Elements / Q000235:genetics*; D005260:Female; D015870:Gene Expression / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008649:Mesonephroma / Q000235:genetics; D009373:Neoplasms, Germ Cell and Embryonal / Q000235:genetics*; D010051:Ovarian Neoplasms / Q000235:genetics*; D013724:Teratoma / Q000235:genetics; D013736:Testicular Neoplasms / Q000235:genetics*
D000906:Antibodies; D004251:DNA Transposable Elements