Mutational Analysis (c.402C>G) of the FOXL2 Gene and Immunohistochemical Expression of the FOXL2 Protein in Testicular Adult Type Granulosa Cell Tumors and Incompletely Differentiated Sex Cord Stromal Tumors

Abstract

Recently a somatic point mutation in the FOXL2 gene has been characterized in ovarian adult type of granulosa cell tumor (ATGCT) (94.6%), thecomas (12.5%), but not in juvenile type of ovarian granulosa cell tumor, other ovarian sex cord tumors and ovarian surface epithelial neoplasms. Whether this mutation is present in testicular ATGCT or incompletely differentiated sex cord stromal tumor (ISCST) is not known. Four ATGCTs, 4 ISCST were immunohistochemically investigated with anti-FOXL2 and 3 ovarian ATGCTs were used as positive control. Weak-to-moderate immunoreactivity was found in all tested testicular and ovarian tumors. PCR and direct sequencing were used for detection of c.402C>G of the FOXL2 gene. No mutation was found in any of the testicular ATGCTs or ISCSTs whereas all ovarian tumors showed the c.402C>G point mutation of the FOXL2 gene. On the basis of this small series of these rare testicular neoplasms, it seems that the c.402C>G mutation of the FOXL2 gene frequently found in adult type of ovarian GCT does not play any significant role in the development of ATGCT and ISCST.