Absence of a FOXL2 mutation (402C→G) in the blood of adult-type granulosa cell tumor patients possessing the FOXL2 mutation.

Recently, a new mutation in FOXL2, c.402C→G leading to a p.C134W change, was reported to be found in 97% of adult-type ovarian granulosa cell tumors (GCTs) tested. In the current study, we compared the FOXL2 sequences of genomic DNA isolated from both GCT and blood. Although the GCTs of patients possessed the FOXL2 mutation, their FOXL2 nucleotide sequences of genomic DNA isolated from matching blood samples lacked the 402C→G mutation. Therefore, we confirmed that the nucleotide alteration of FOXL2 is due to a somatic mutation and demonstrated that sequencing of blood DNA for the detection of the FOXL2 mutation is not a useful method for the diagnosis of GCT.