[Juvenile granulosa-cell tumor: clinical and molecular expression].

Ovarian sex cord-stromal tumors are rare tumors that originate from the nongerminal cells of ovary. Two decades ago, the identification of juvenile granulosa-cell tumors (GCT), as a specific entity inside this group, allowed a better treatment of these tumors in children. However, little data have been reported on the natural course of the disease and reliable prognostic factors have not been yet defined. We here review the clinical and genetics aspects of granulosa tumors, based on a series of 40 children. This national collaborative study involved the French Society of Children Cancer and eight clinical departments of pediatric endocrinology. We found that early diagnosis of a tumor, revealed by clinical signs of hyperoestrogeny, is an important prognostic factor. The pathophysiology of these tumors is still debatable and several cellular- and molecular-abnormal signals could be implicated in their development. The role of growth factors and oncogenes through the signaling pathway of MAP kinase is still discussed. According to our data, FSH signaling-transduction pathway, such as a constitutionally activated Galphas, could also be implicated in the induction of granulosa cell proliferation and seems to modulate the invasiveness of the tumor. Last, we have described a low-expression pattern or an extinction of an ovarian-determination gene, FOXL2, which is related to a worse prognosis of this tumor.