title: Expression of pRb and p16INK4 in human thymic epithelial tumors in relation to the presence of human polyomavirus 7.
abstract: BACKGROUND
  We have recently reported the presence of the Human polyomavirus 7 (HPyV7) in human thymic epithelial tumors as assessed by diverse molecular techniques. Here we report on the co-expression of p16, retinoblastoma protein (pRb) and phosphorylated retinoblastoma protein (phospho-Rb) in human thymic epithelial tumors in relation to HPyV7.
  
  
  METHODS
  PRB, phospho-RB and p16 expression was assessed by immuno-histochemistry in 37 thymomas and 2 thymic carcinomas. 17 thymomas (46 %) and 1 thymic carcinoma (50 %) were recently tested positive for HPyV7. In addition, 20 follicular hyperplasias were tested.
  
  
  RESULTS
  Expression of pRb was observed in 35 thymomas (94.6 %), in 16 thymomas (43.2 %) the expression was strong. Phospho-Rb was observed in 31 thymomas (83.8 %). 19 thymomas (51.4 %) showed immunoreactivity for p16 of which 8 thymomas revealed very strong p16 expression. No p16 expression was detected in thymic carcinomas. In addition, no significant correlation between the presence of HPyV7 and pRb-, phospho-Rb- and p16-expression could be established. No correlation between pRb, phospho-Rb, p16 and WHO staging, Masaoka-Koga staging or the presence of MG was found. All 20 follicular hyperplasias showed expression of pRb and less expression of phospho-Rb.
  
  
  CONCLUSIONS
  Although polyomaviruses have been shown to interact with cell cycle proteins no correlation between the presence of HPyV7 and the expression of pRb, phospho-Rb and p16 in human thymic epithelial tumors was observed. In as much HPyV7 contributes to human thymomagenesis remains to be established. Our data indicate pRb, phospho-Rb and p16 expression are rather unlikely to be involved in HPyV7 related thymomagenesis.
authors.affiliation: Department of Cardiothoracic Surgery, Maastricht University Medical Centre, Maastricht, The Netherlands. m.keijzers@mumc.nl.|Department of Pulmonology, Maastricht University Medical Centre, Maastricht, The Netherlands. m.keijzers@mumc.nl.|GROW-School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands. m.keijzers@mumc.nl.
authors.forename: Marlies
authors.initials: M
authors.lastname: Keijzers
authors.affiliation: Department of Pathology, Maastricht University Medical Centre, P. Debyelaan 25, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands. dorit.rennspiess@mumc.nl.|GROW-School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands. dorit.rennspiess@mumc.nl.
authors.forename: Dorit
authors.initials: D
authors.lastname: Rensspiess
authors.affiliation: Department of Pathology, Maastricht University Medical Centre, P. Debyelaan 25, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands. sreedhar.pujari@mumc.nl.|GROW-School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands. sreedhar.pujari@mumc.nl.
authors.forename: Sreedhar
authors.initials: S
authors.lastname: Pujari
authors.affiliation: Department of Pathology, Maastricht University Medical Centre, P. Debyelaan 25, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands. m.abdulhamid@mumc.nl.|GROW-School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands. m.abdulhamid@mumc.nl.
authors.forename: Myrurgia A
authors.initials: MA
authors.lastname: Abdul-Hamid
authors.affiliation: Department of Pulmonology, Maastricht University Medical Centre, Maastricht, The Netherlands. m.hochstenbag@mumc.nl.|GROW-School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands. m.hochstenbag@mumc.nl.
authors.forename: Monique
authors.initials: M
authors.lastname: Hochstenbag
authors.affiliation: Department of Pulmonology, Maastricht University Medical Centre, Maastricht, The Netherlands. a.dingemans@mumc.nl.|GROW-School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands. a.dingemans@mumc.nl.
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Dingemans
authors.affiliation: Department of Internal Medicine IV, University Hospital Aachen, Aachen, Germany. azurhausen@ukaachen.de.
authors.forename: Anna Kordelia
authors.initials: AK
authors.lastname: Kurz
authors.affiliation: Department of Pathology, Maastricht University Medical Centre, P. Debyelaan 25, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands. a.haugg@mumc.nl.|GROW-School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands. a.haugg@mumc.nl.
authors.forename: Anke
authors.initials: A
authors.lastname: Haugg
authors.affiliation: Department of Cardiothoracic Surgery, Maastricht University Medical Centre, Maastricht, The Netherlands. j.g.maessen@mumc.nl.
authors.forename: Jos G
authors.initials: JG
authors.lastname: Maessen
authors.affiliation: Department of Neuro-Science, Maastricht University, School of Mental Health and Neuroscience (MHeNS), Maastricht, The Netherlands. m.debaets@maastrichtuniversity.nl.
authors.forename: Marc H
authors.initials: MH
authors.lastname: De Baets
authors.affiliation: Department of Pathology, Maastricht University Medical Centre, P. Debyelaan 25, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands. axel.zurhausen@mumc.nl.|GROW-School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands. axel.zurhausen@mumc.nl.
authors.forename: Axel
authors.initials: A
authors.lastname: Zur Hausen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D008875:Middle Aged; D009375:Neoplasms, Glandular and Epithelial / Q000175:diagnosis / Q000378:metabolism* / Q000821:virology*; D011120:Polyomavirus / Q000302:isolation & purification*; D016160:Retinoblastoma Protein / Q000378:metabolism*; D013945:Thymoma / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology; D013953:Thymus Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000821:virology*
chemical_list: D019941:Cyclin-Dependent Kinase Inhibitor p16; D016160:Retinoblastoma Protein