PRL-positive immunohistochemistry of removed ovarian tissue, the presence of a PRL concentration gradient between the tumor vein and the peripheral vein, and a decrease in the PRL concentration in the blood after removal of the gonadoblastoma provide evidence of ectopic PRL synthesis in vivo by the ovarian tumor.[7] Case reports of hyperprolactinemia in ovarian malignant small cell tumors of pulmonary type[8] and in juvenile granulosa cell tumors[9] are also presented. This evidence concerns the gene PRL and gonadoblastoma.