Activating mutation of the stimulatory G protein (GSP) as a putative cause of ovarian and testicular human stromal Leydig cell tumors

• Published in: The journal of clinical endocrinology and metabolism 1998-06, Vol.83 (6), p.2074-2078
• Main Authors: VILLARES FRAGOSO, M. C. B, LATRONICO, A. C, CARVALHO, F. M, ZERBINI, M. C. N, MARCONDES, J. A. M, ARAUJO, L. M. B, LANDO, V. S, FRAZZATTO, E. T, MENDONCA, B. B, VILLARES, S. M. F
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Biological and medical sciences; Child; DNA, Neoplasm - analysis; Electrophoresis, Agar Gel; Exons; Female; GTP-Binding Protein alpha Subunit, Gi2; GTP-Binding Protein alpha Subunits, Gi-Go; GTP-Binding Protein alpha Subunits, Gs - genetics; GTP-Binding Proteins - genetics; Gynecology. Andrology. Obstetrics; Humans; Leydig Cell Tumor - genetics; Male; Male and female genital diseases. Gonadal dysgenesis. Hermaphroditism. Sex hormones resistance; Medical sciences; Middle Aged; Mutation; Ovarian Neoplasms - genetics; Polymerase Chain Reaction; Proto-Oncogene Proteins - genetics; Sequence Analysis, DNA; Stromal Cells; Tropical medicine
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jc.83.6.2074

Activating mutations of the G protein genes have been associated with the development of several endocrine neoplasms. Such activating mutations, gip2, affecting the alpha-subunit of the G alpha i2 protein were previously described by a single group in 30% of ovarian sex cord stromal tumors. Other activating mutations of the alpha-subunit of the Gs (gsp) have been identified in GH-secreting and nonfunctioning pituitary tumors, autonomous thyroid adenomas, and all affected McCune-Albright tissues, but not in sex cord stromal tumors. In the present study, we investigated the presence of gip2 and gsp mutations in 14 human sex cord stromal tumors. Six Leydig cell tumors (4 ovaries and 2 testes), 2 thecomas, 2 granulosa cell tumors, 3 androblastomas, and 1 gonadoblastoma (sex cord and germ cell) were included in this study. Genomic DNA was obtained from either fresh-frozen tumor tissues or paraffin-embedded sections and in some cases from blood samples. Using PCR, denaturing gradient gel electrophoresis, and direct sequencing, we detected 4 tumors (66.6%) with the gsp mutation (R201C) in our series of ovarian and testicular Leydig cell tumors. In contrast, no gip2 mutations were found in any of the sex cord stromal tumors studied. In conclusion, our findings suggest that the putative oncogene gsp may play a significant role in the molecular mechanism of these tumors.