Expression of the insulin-like growth factor (IGF) system and steroidogenic enzymes in canine testis tumors

• Published in: Reproductive biology and endocrinology Vol. 1; no. 1; p. 22
• Main Authors: Peters, Monique A J, Mol, Jan A, van Wolferen, Monique E, Oosterlaken-Dijksterhuis, Marja A, Teerds, Katja J, van Sluijs, Frederik J
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 14-02-2003; BioMed Central; BMC
• Subjects: 3-Oxo-5-alpha-Steroid 4-Dehydrogenase; Animals; Aromatase - biosynthesis; Aromatase - genetics; Dog Diseases - genetics; Dog Diseases - metabolism; Dogs; Enzyme Induction; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Gonadal Steroid Hormones - biosynthesis; Insulin-Like Growth Factor Binding Proteins - biosynthesis; Insulin-Like Growth Factor Binding Proteins - genetics; Leydig Cell Tumor - genetics; Leydig Cell Tumor - metabolism; Leydig Cell Tumor - veterinary; Male; Neoplasm Proteins - biosynthesis; Neoplasm Proteins - genetics; Receptors, Androgen - biosynthesis; Receptors, Androgen - genetics; Receptors, Somatomedin - biosynthesis; Receptors, Somatomedin - genetics; Reverse Transcriptase Polymerase Chain Reaction; Seminoma - genetics; Seminoma - metabolism; Seminoma - veterinary; Sertoli Cell Tumor - genetics; Sertoli Cell Tumor - metabolism; Sertoli Cell Tumor - veterinary; Somatomedins - biosynthesis; Somatomedins - genetics; Testicular Neoplasms - genetics; Testicular Neoplasms - metabolism; Testicular Neoplasms - veterinary; Testis - enzymology
• ISSN: 1477-7827; 1477-7827
• DOI: 10.1186/1477-7827-1-22

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.