title: Deregulation of the G1/S-phase control in human testicular germ cell tumours.
abstract: Deregulated cell cycle and defective genome-integrity checkpoints are among the hallmarks of cancer. Here we summarize our recent studies of key components of the GI/S machinery in normal human spermatogenesis, and their abnormalities in testicular germ cell tumours (TGCTs), with special emphasis on carcinoma in situ lesions (CIS). Our combined immunohistochemical and immunoblotting analyses of normal human adult and fetal testes, CIS, seminomas, embryonal carcinomas, and teratomas, revealed an 'unorthodox' spectrum of defects within the so-called RB pathway in TGCTs. The early aberrations included lack of expression of the retinoblastoma tumour suppressor (pRB) and the CDK inhibitor pl9ink4d, and overexpression of cyclin D2. Progression from CIS to invasive TGCTswas associated with loss of another two CDK inhibitors and tumour suppressors: pl6ink4a and pl8ink4c. We also found the lack of pRB and pl9ink4d in fetal gonocytes, the candidate target cell for all types of TGCTs. These findings, together with the status of the Chk2-p53 DNA-integrity checkpoint, are considered in relation to the origin, biology and pathogenesis of TGCTs, and potential implications of the GI/S defects for the curability of these tumours.
authors.affiliation: Department of Cell Cycle and Cancer, institute of Cancer Biology, Danish Cancer Society, DK-2100 Copenhagen, Denmark.
authors.forename: Jirina
authors.initials: J
authors.lastname: Bartkova
authors.forename: Ewa
authors.initials: E
authors.lastname: Rajpert-De Meyts
authors.forename: Niels E
authors.initials: NE
authors.lastname: Skakkebaek
authors.forename: Jiri
authors.initials: J
authors.lastname: Lukas
authors.forename: Jiri
authors.initials: J
authors.lastname: Bartek
mesh_terms: D000328:Adult; D000818:Animals; D002278:Carcinoma in Situ / Q000209:etiology / Q000473:pathology; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D002471:Cell Transformation, Neoplastic; D056742:Cyclin D2; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism; D050763:Cyclin-Dependent Kinase Inhibitor p18; D050764:Cyclin-Dependent Kinase Inhibitor p19; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors; D016213:Cyclins / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000378:metabolism; D016193:G1 Phase; D018237:Germinoma / Q000209:etiology* / Q000473:pathology; D006801:Humans; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D010766:Phosphorylation; D016160:Retinoblastoma Protein / Q000032:analysis / Q000378:metabolism; D016196:S Phase; D013091:Spermatogenesis; D013736:Testicular Neoplasms / Q000209:etiology* / Q000473:pathology; D013737:Testis / Q000196:embryology / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000378:metabolism
chemical_list: C080336:CCND2 protein, human; C493971:CDKN2C protein, human; C493974:CDKN2D protein, human; C486196:Ccnd2 protein, mouse; C493972:Cdkn2c protein, mouse; C493975:Cdkn2d protein, mouse; D018797:Cell Cycle Proteins; D056742:Cyclin D2; D019941:Cyclin-Dependent Kinase Inhibitor p16; D050763:Cyclin-Dependent Kinase Inhibitor p18; D050764:Cyclin-Dependent Kinase Inhibitor p19; D016213:Cyclins; D004791:Enzyme Inhibitors; D016160:Retinoblastoma Protein; D025521:Tumor Suppressor Proteins; D018844:Cyclin-Dependent Kinases