Presence of TSPY transcript and absence of transcripts of other Y chromosomal genes in a case of microscopic gonadoblastoma

Background: Gonadoblastoma is found almost exclusively in people with gonadal dysgenesis and Y chromosomal DNA fragment. Accordingly, GBY (gonadoblastoma locus on the Y chromosome) has been mapped to the Y chromosome. Testis-specific protein Y-encoded (TSPY) gene may participate in the oncogenesis of gonadoblastoma expression of TSPY in the tumor tissue. This might suggest TSPY as a candidate gene for gonadoblastoma. Case report: A 14-year-old phenotypic girl with typical features of gonadal dysgenesis and a normal male karyotype. She underwent prophylactic bilateral gonadectomy to prevent future malignant changes of streak gonads. Histopathologic examination revealed microscopic foci of gonadoblastoma on the left side of ovary. We tested transcripts of 14 Y chromosomal genes by RT-PCR (TSPY, DAZ, BPY1 and BPY2, PRY, XKRY, CDY1 and CDY2, TTY1 and TTY2, PRKY, RBMY1, DBY and USP9Y), and only transcript of TSPY was detectable in the tumor tissue. Conclusion: Expression of TSPY in microscopic gonadoblastoma might suggest important roles of TSPY, but not other Y chromosomal genes, in the very early stage of oncogenesis.