title: Expression of the insulin-like growth factor (IGF) system and steroidogenic enzymes in canine testis tumors.
abstract: Testis tumors occur frequently in dogs. The main types of tumors are Sertoli cell tumors, seminomas, and Leydig cell tumors. Mixed tumors and bilateral occurrence of tumors may be encountered frequently. To elucidate the possible relationship between the insulin-like growth factor (IGF) system and the development of different types of testis tumors in dogs, the expression of insulin-like growth factor-I and II (IGF-I and IGF-II), their type I receptor (IGF-IR), and their binding proteins (IGFBPs) was examined. In addition the expression of the steroidogenic enzymes p450-aromatase and 5alpha-reductase type I and type II, and the androgen receptor (AR) was investigated by a semiquantitative reverse-transcriptase PCR (RT-PCR). Both normal testes and testes with tumors were studied. In normal testes a clear expression of IGF-I, IGF-II, IGF-IR, IGFBP2, IGFBP4 and IGFBP5 was found. Expression of IGFBP1 and IGFBP3 was weak. There was also clear expression of the steroidogenic enzymes 5alpha-reductase, aromatase, and the AR. Quantification of RT-PCR products revealed significantly less expression of IGFBP1, IGF-I, and 5alpha-reductase type I in Sertoli cell tumors and seminomas. Leydig cell tumors and mixed tumors had a significantly higher expression of IGFBP4 and IGF-IR than normal testes. The expression of aromatase was lower in seminomas and in mixed tumors. The expression of AR, IGF-II and IGFBP2, IGFBP3, IGFBP5, and 5alpha-reductase type II did not differ among the different types of tumors. It was concluded that Sertoli cell tumors and seminomas have a comparable expression of the IGF system while Leydig cell tumors have a different pattern, suggesting difference in pathobiology among these types of tumors.
authors.affiliation: Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Universiteit Utrecht, The Netherlands. majpeters@wish.net
authors.forename: Monique A J
authors.initials: MA
authors.lastname: Peters
authors.forename: Jan A
authors.initials: JA
authors.lastname: Mol
authors.forename: Monique E
authors.initials: ME
authors.lastname: van Wolferen
authors.forename: Marja A
authors.initials: MA
authors.lastname: Oosterlaken-Dijksterhuis
authors.forename: Katja J
authors.initials: KJ
authors.lastname: Teerds
authors.forename: Frederik J
authors.initials: FJ
authors.lastname: van Sluijs
mesh_terms: D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase; D000818:Animals; D001141:Aromatase / Q000096:biosynthesis / Q000235:genetics; D004283:Dog Diseases / Q000235:genetics / Q000378:metabolism*; D004285:Dogs; D004790:Enzyme Induction; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D012739:Gonadal Steroid Hormones / Q000096:biosynthesis*; D018969:Insulin-Like Growth Factor Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D007984:Leydig Cell Tumor / Q000235:genetics / Q000378:metabolism / Q000662:veterinary; D008297:Male; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics; D011944:Receptors, Androgen / Q000096:biosynthesis / Q000235:genetics; D017451:Receptors, Somatomedin / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018239:Seminoma / Q000235:genetics / Q000378:metabolism / Q000662:veterinary; D012707:Sertoli Cell Tumor / Q000235:genetics / Q000378:metabolism / Q000662:veterinary; D013002:Somatomedins / Q000096:biosynthesis / Q000235:genetics; D013736:Testicular Neoplasms / Q000235:genetics / Q000378:metabolism / Q000662:veterinary*; D013737:Testis / Q000201:enzymology
chemical_list: D012739:Gonadal Steroid Hormones; D018969:Insulin-Like Growth Factor Binding Proteins; D009363:Neoplasm Proteins; D011944:Receptors, Androgen; D017451:Receptors, Somatomedin; D013002:Somatomedins; D001141:Aromatase; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase