Foxl-2 in gonad development and pathology

The Foxl-2 gene is involved in eyelid and ovary development. Mutations can lead to a shortened protein and malformations such as BPES associated or not to POF. Forkhead point mutation C134W is a marker of adult type granulosa cell tumors only. Foxl-2 dysregulation is also present in DSD and DSD associated tumors such as Gonadoblastoma and gonadoblastoma like intratubular undetermined germ cell neoplasia. A similar spectrum of pathology involvement is also found for WT1 and RET and gives a new insight into the relationship between development, malformations and oncogenesis.

Testis-specific protein Y-encoded gene is expressed in early and late stages of gonadoblastoma and testicular carcinoma in situ

The testis-specific protein Y-encoded gene (TSPY) is a tandem repeat gene located at the critical region for the gonadoblastoma locus on Y chromosome that predisposes the dysgenetic gonads of intersex individuals to oncogenesis. The expression and molecular properties of TSPY suggest that it is the putative gene for the gonadoblastoma locus on Y chromosome. In this study, we examined the expression of TSPY and other germ cell tumor markers in 4 cases of gonadoblastoma using immunostaining techniques. Our results showed that TSPY expression was closely associated with initiation and various stages of gonadoblastoma development. TSPY protein localized with established germ cell tumor markers, such as the placental alkaline phosphatase, c-KIT, and OCT3/4, in the same tumor cells of both gonadoblastoma and adjacent carcinoma in situ, the precursor for germ cell tumors. These findings support the candidacy of TSPY as the gene for the gonadoblastoma locus on Y chromosome and suggest that TSPY could be a significant marker for these types of germ cell tumors.

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.

Identification of germ cells at risk for neoplastic transformation in gonadoblastoma: an immunohistochemical study for OCT3/4 and TSPY

Carcinoma in situ (CIS) is the precursor of malignant testicular germ cell tumors (GCTs) of adolescents and young adults, being the neoplastic counterpart of primordial germ cells/gonocytes. Carcinoma in situ cells will develop into invasive seminoma/nonseminoma. Gonadoblastoma (GB) is the precursor of invasive GCTs in dysgenetic gonads, predominantly dysgerminoma (DG). In this process, part of the Y chromosome (GBY region) is involved, for which TSPY is a candidate gene. A detailed immunohistochemical survey was performed for the known diagnostic markers, germ cell/placental alkaline phosphatase (PLAP), c-KIT, and OCT3/4, as well as testis-specific protein on the Y chromosome (TSPY) on a series of GBs, and adjacent invasive DGs. All 5 patients were XY individuals (4 females and 1 male). In contrast to c-KIT, PLAP was positive in all cases. The immature germ cells of GBs were positive for OCT3/4, whereas the mature germ cells were negative for this marker, but positive for TSPY. In every GB, a minor population of germ cells positive for both markers could be identified, similar to most CIS cells and early invasive DG. On progression to an invasive tumor, TSPY can be lost, a process that is also detectable in invasive testicular GCTs compared to CIS. These results indicate that GB is a heterogeneous mix of germ cells, in which the OCT3/4-positive cells have the potential to undergo progression to an invasive tumor. These early invasive stages are initially also positive for TSPY (like CIS), supporting a positive selection mechanism. Therefore, OCT3/4 in combination with TSPY is valuable to identify malignant germ cells in dysgenetic gonads. This could allow better prediction of the risk of progression to a GCT. In addition, the data support the model that GB represents the earliest accessible developmental stage of malignant GCTs.

Gonadoblastoma: evidence for a stepwise progression to dysgerminoma in a dysgenetic ovary

Gonadoblastomas are neoplasms of dysgenetic gonads which may undergo regression or become overgrown by malignant germ cell tumors (mGCTs). Since little is known about their relationship to normal gonadal development and mGCTs, we studied the phenotype and antigenic profile of gonadoblastomas in comparison with adjacent dysgerminomas and fetal gonads. Three cases of gonadoblastomas and fetal gonads of both sexes were analyzed using oncofetal markers to M2A-antigen (M2A), germ cell alkaline phosphatase (PLAP/GCAP), receptor tyrosine kinase c-kit (c-kit), and somatic angiotensin converting enzyme (sACE) as well as the proliferation marker MIB-1. Morphologically, microfollicular pattern of gonadoblastomas showed a fetal germ cell organization reminiscent of oocytic clusters of fetal ovaries. They contained both cell types, similar to oocytes (M2A-, GCAP-, c-kit+/-, sACE-) and oogonia (M2A+, GCAP+, c-kit+, sACE+). The percentage of germ cells immunoreactive for oncofetal markers and the proliferation index increased from microfollicular over coronary patterns to adjacent dysgerminomas. Supportive cells of gonadoblastomas showed a uniform phenotype (CK18+, vimentin+, sACE+, alpha-inhibin+, M2A-) but in contrast to fetal germ cells lacked a clear equivalence to fetal tissues. Our results show that gonadoblastomas mimic female fetal ovary and exhibit a stepwise progression from follicular pattern to coronary pattern and finally to dysgerminomas.

Involvement of E-cadherin and beta-catenin in germ cell tumours and in normal male fetal germ cell development

Intercellular contacts, mediated by E-cadherin, are essential for germ cell migration and maturation. Furthermore, it has been suggested that decrease or loss of E-cadherin correlates with tumour progression and invasive behaviour. beta-catenin is involved in a number of different processes, including cell--cell interaction when bound to cadherins, and determination of cell fate in pluripotent cells when activated via the Wnt signal-transduction pathway. To shed more light on the role of these factors in normal fetal germ cell development and the pathogenesis of germ cell tumours (GCTs), the present study investigated the presence and localization of E-cadherin and beta-catenin by immunohistochemistry. E-cadherin was only weakly expressed in or absent from fetal germ cells of the second and third trimesters, and was not expressed in carcinoma in situ/intratubular germ cell neoplasia unclassified (CIS/ITGCNU) and gonadoblastoma, the precursor of an invasive GCT in dysgenetic gonads. In GCTs, it was generally not expressed in seminoma and dysgerminoma, but was found in the vast majority of non-seminoma cells. beta-catenin was found in the cytoplasm of fetal germ cells at all gestational ages and in spermatogenesis in post-pubertal testes. It was also present in CIS/ITGCNU and gonadoblastoma. Whereas seminomas and dysgerminoma were negative, non-seminoma cells were frequently found to express beta-catenin. Expression of both factors therefore reflects the degree of differentiation of these tumours. No differences for either E-cadherin or beta-catenin were observed between samples of tumours resistant or sensitive to chemotherapy, and E-cadherin expression did not correlate with vascular invasion. E-cadherin and beta-catenin therefore play a role in both normal and malignant germ cell development and differentiation that warrants further investigation, but they seem to be of limited value as predictive or prognostic factors in GCTs.

OCT4: a novel biomarker for dysgerminoma of the ovary

The prognosis and therapy for dysgerminomas are different from those of other ovarian tumor types, making accurate diagnosis imperative for patient care. OCT4 (POU5F1) is a transcription factor involved in the regulation of pluripotency during embryonic development. It can be detected in both pluripotent cells and other early germ cells. This study examines the expression of OCT4 in both dysgerminoma and nondysgerminomatous neoplasms involving the ovary. Formalin-fixed, paraffin-embedded cell blocks of 33 cases of dysgerminoma including 2 cases of gonadoblastoma associated with dysgerminoma and 3 cases of metastatic dysgerminoma, and 111 cases of nondysgerminomatous neoplasms involving the ovary were stained using the antibody against OCT4. All cases of dysgerminomas and gonadoblastomas were positive for OCT4 with strong nuclear staining. More than 90% of dysgerminoma cells in each case showed diffuse strong nuclear staining. In addition, 3 metastatic dysgerminomas also showed uniform strong nuclear staining. All nondysgerminomatous tumors (mature teratoma, 14; yolk sac tumor, 4; Sertoli-Leydig cell tumor, 15; granulosa cell tumor, 22; Brenner tumor, 3; carcinoid tumor, 4; struma ovarii, 2; fibroma, 5; thecoma, 1; serous adenocarcinoma, 5; endometrioid adenocarcinoma, 4; small cell carcinoma, 6; stromal sarcoma, 1; malignant lymphoma, 6; metastatic malignant melanoma, 1; metastatic carcinoid, 2; metastatic small cell carcinoma, 1; and metastatic lobular carcinoma of the breast, 1) were negative for OCT4, except for some cases of clear cell adenocarcinoma of the ovary. Four of 14 clear cell adenocarcinomas showed focal positive nuclear immunoreactivity for OCT4. OCT4 is a sensitive and relatively specific biomarker for the detection of dysgerminoma. It may also be useful in the diagnosis of gonadoblastoma, which contains similar cells and may be associated with dysgerminoma. OCT4 may aid in the detection of small foci of metastatic dygerminoma in extraovarian sites and may also help distinguish dysgerminoma from other primary and metastatic tumors of the ovary.

Gonadoblastoma and dysgerminoma associated with XY gonadal dysgenesis in an adolescent with chronic renal failure: a case of Frasier syndrome

STUDY OBJECTIVES

To report a rare reason for primary amenorrhea, a Frasier syndrome, XY gonadal dysgenesis associated with renal failure with eventual development of gonadoblastoma. To study immunohistochemical analysis of gonadoblastoma and dysgerminoma. To analyze the possibility of androgen receptor mutation in this rare syndrome.

METHODS

We report a case of a 16-yr-old female with this syndrome. She underwent a laparoscopic bilateral gonadectomy and salpingectomy. A histopathological examination revealed gonadoblastoma with focal malignant dysgerminoma in the left dysgenetic gonad and an immunohistochemical of these fairly rare, malignant tumors. An androgen receptor was coded. Analysis was done.

RESULTS

Immunohistochemical analysis showed that inhibin was strongly positive in gonadoblastoma but negative in dysgerminoma. No mutations of the androgen receptor gene were found.

CONCLUSIONS

Inhibin positivity in gonadal stroma and in gonadoblastoma may indicate hormonal activity causing advanced puberty in patients with XY gonadal dysgenesis.

Utility of immunostaining for S-100 protein subunits in gonadal sex cord-stromal tumors, with emphasis on the large-cell calcifying Sertoli cell tumor of the testis

This study concerns the immunohistochemical localization of S-100 alpha, S-100 beta, and whole brain S-100 (wbS-100) in testicular large-cell calcifying Sertoli cell tumor (LCCSCT). We examined 8 LCCSCTs (7 benign and 1 malignant), 6 Sertoli cell tumors not otherwise specified (SCTs-NOS), 6 Leydig cell tumors (LCTs), 5 ovarian Sertoli-Leydig cell tumors (SLCTs), and 7 gonadoblastomas (GBLs). The 8 LCCSCTs showed immunoreactivity for S-100 alpha, S-100 beta, and wbS-100. Five of the 6 LCTs and the Leydig cell components in the ovarian SLCTs stained positively for S-100 alpha and wbS-100 but were negative for S-100 beta. SCTs-NOS and the Sertoli cell components in the SLCTs occasionally showed focal and weak/moderate positivity for S-100 alpha, S-100 beta, and wbS-100. Sex cord cells of the GBLs were positive for S-100 beta and wbS-100 and negative for S-100 alpha. Germ cell elements of the GBLs were negative for S-100 alpha, S-100 beta, and wbS-100. In nonneoplastic testicular parenchyma adjacent to the above-mentioned tumors, there was S-100 alpha reactivity in Leydig cells, rete testis, and a few Sertoli cells. S-100 beta reactivity was seen in a few Sertoli cells, Schwann cells, and some endothelial cells. WbS-100 reactivity was present in Leydig cells, a few Sertoli cells, rete testis, Schwann cells, and some endothelial cells. The results indicate that S-100 alpha and S-100 beta can potentially be used as immunohistochemical markers for LCCSCT, especially when differentiating it from LCT, which may mimic LCCSCT on routine histopathology. Although the biological significance of both S-100 subunits expression in LCCSCT remains unknown, these notable calcium-binding proteins may be associated with the characteristic calcification in LCCSCT through regulation of calcium levels in the tumor cells.

Detection of TSPY protein in a unilateral microscopic gonadoblastoma of a Turner mosaic patient with a Y-derived marker chromosome

Gonadoblastomas are seen almost exclusively in dysgenetic gonads of patients with a chromosomal mosaicism of 45,X and an additional Y-bearing cell line. This paper presents a case of a Turner mosaic patient with 45,X/46,X,+mar karyotype, who developed a unilateral microscopic gonadoblastoma. Cytogenetic and molecular analysis confirmed a Y-chromosomal origin of the marker chromosome, with a deletion of the distal Yq arm and the proposed region of a so far undefined gonadoblastoma locus (GBY) present. One of the candidate genes within the postulated GBY region is TSPY (testis-specific protein Y-encoded). To study the TSPY protein expression, an anti-fusion protein antibody was used for immunohistochemistry of the patient's gonads. In contrast to the dysgenetic gonad, an intense immunoreaction was found in gonadoblastoma tumour cells of the other gonad. These results confirm the high level of TSPY protein expression by these cells and demonstrate the value of this antibody as an additional marker to confirm the diagnosis of gonadoblastoma.

Inhibin expression in ovarian tumors and tumor-like lesions: an immunohistochemical study

We investigated 203 ovarian tumors and tumor-like lesions for inhibin expression using a monoclonal anti-inhibin alpha antibody. Inhibin was present in the tumor cells in all 14 primary adult granulosa cell tumors (4 luteinized) plus 3 metastatic, all 10 primary juvenile granulosa cell tumors plus 1 metastatic, 10 of 11 thecomas, 3 of 11 fibromas, 4 of 11 sclerosing stromal tumors, 6 of 11 Sertoli cell tumors (1 oxyphilic), 7 of 11 Sertoli-Leydig cell tumors, 1 gynandroblastoma, 10 primary ovarian sex cord tumors with annular tubules plus 2 metastatic, 8 of 9 steroid cell tumors, both pregnancy luteomas, 1 of 2 unclassified sex cord tumors, 2 of 5 gonadoblastomas, 9 of 10 female adnexal tumors of probable wolffian origin, and in the non-neoplastic stroma of many carcinomas and germ cell tumors. The tumor cells were inhibin-negative in 10 fibrosarcomas, 12 small cell carcinomas of hypercalcemic type, 24 germ cell tumors (except for a focus of inhibin-positive syncytiotrophoblast in one case), and 17 ovarian carcinomas. Two of the three inhibin-positive fibromas showed diffuse immunostaining and were associated with evidence of estrogenic activity. Among nine Sertoli-Leydig cell tumors with available clinical data, four that were more than minimally inhibin-positive were accompanied by androgenic manifestations; five inhibin-negative or only minimally positive tumors lacked such evidence. Inhibin immunostaining may be useful in the differential diagnosis of inhibin-positive sex cord tumors versus histologically similar inhibin-negative neoplasms, but inhibin negativity does not preclude a diagnosis of sex cord tumor. The unexpected, common inhibin positivity of female adnexal tumors of probable wolffian origin indicates that inhibin staining cannot be used to differentiate these tumors from Sertoli cell tumors. Inhibin immunostaining is also helpful in identifying potential steroid hormone-secreting cells in the non-neoplastic stromal component of epithelial, germ cell, and other ovarian tumors.