title: Clonality of combined testicular germ cell tumors of adults.
abstract: BACKGROUND
  Recently we have shown, by combining in situ hybridization and immunohistochemistry, that carcinoma in situ (CIS) adjacent to seminoma (CIS/SE), like SE, usually contains three copies of the centromeric region of chromosome 15/tumor cell. In contrast, CIS adjacent to nonseminomatous testicular germ cell tumors of adults (CIS/NS), as well as NS itself, have two copies.
  
  
  METHODS
  In the present study we have used this approach to investigate the clonal origin of the SE and NS components of combined tumors (CTs). We counted the number of copies of chromosome 15 centromeric regions in tumor cell nuclei of the CIS, SE, and NS components of nine CTs.
  
  
  RESULTS
  We show that the number of copies of centromeric regions of chromosome 15 in both the SE and the NS component, and the adjacent CIS of the same CT, may be high (SE-pattern) or low (NS-pattern). In two cases, the copy numbers were high in the SE component and its adjacent CIS, and low in the NS component and its adjacent CIS.
  
  
  CONCLUSIONS
  The data suggest that in most CTs the SE and the NS components have a monoclonal origin, and that karyotype evolution in CIS and the invasive tumor is very similar.
authors: Laboratory of Experimental Patho-Oncology, Dr. Daniel den Hoed Cancer Center, Rotterdam, The Netherlands.
authors: A J
authors: AJ
authors: Gillis
authors: L H
authors: LH
authors: Looijenga
authors: B
authors: B
authors: de Jong
authors: J W
authors: JW
authors: Oosterhuis
mesh_terms: D000328:Adult; D002278:Carcinoma in Situ / Q000235:genetics / Q000473:pathology*; D002999:Clone Cells; D018237:Germinoma / Q000235:genetics / Q000473:pathology*; D006801:Humans; D007124:Immunoenzyme Techniques; D017403:In Situ Hybridization; D007621:Karyotyping; D008297:Male; D011003:Ploidies; D018239:Seminoma / Q000235:genetics / Q000473:pathology*; D013736:Testicular Neoplasms / Q000235:genetics / Q000473:pathology*