[98]). Some studies have recently identified the gsp oncogene in ovarian granulosa cell tumors and testicular stromal Leydig cell tumors as a possible cause of tumorigenesis and as a possible prognostic marker [99, 100]. In a more recent study, 5 of 30 patients with clear cell renal carcinoma have been shown to carry constitutively activating Gsα mutations in the tumor tissue [101]. Hence, the gsp oncogene can be present in a wide variety of tumors that mostly, but not exclusively, involve classic endocrine tissues. Data from transgenic mouse models and cell culture assays have shown that constitutive Gsα activity can lead to hyperplasia and increased hormone secretion in endocrine cells [102, 103]. However, although a recent study implicates sustained activation of extracellular signal-regulated kinase in increased hormone secretion [104], the signaling pathways downstream of the gsp oncogene currently remain incompletely understood.
