DNA topoisomerase I and II expression in drug resistant germ cell tumours

A small number of testicular germ cell tumours are refractory to current chemotherapy regimens. DNA topoisomerase I is the target for several new drugs and a potential candidate treatment for chemorefractory germ cell tumours. DNA topoisomerase II alpha is the target for etoposide, which is currently used regularly in germ cell tumour treatment. The expression of DNA topoisomerase I and II alpha were therefore assessed immunohistochemically in a range of testicular tumours, especially those with persistent malignant elements on retroperitoneal lymph node dissection. Pre-chemotherapy orchidectomy specimens were matched with post-chemotherapy retroperitoneal lymph node dissections to examine changes in expression. There was considerable variation in the expression of topoisomerase I in different tumour types. Both yolk sac tumours and teratoma, mature showed universal expression of topoisomerase I, while 38% of seminomas and 30% of embryonal carcinomas were positive. Strong topoisomerase II alpha expression was found in embryonal carcinoma. There was a negative correlation between topoisomerase I and II alpha expression (P=0.004) and downregulation of topoisomerase II alpha after chemotherapy (P=0.02). Topoisomerase I expression appears to increase in those cases with residual teratoma, mature, but is largely unchanged in those cases remaining as embryonal carcinoma. These results suggest that topoisomerase I inhibitors may be useful in chemorefractory germ cell tumours, especially yolk sac tumours and where there are unresectable residual teratoma, mature deposits.     

Glycolipids of human primary testicular germ cell tumours.

The glycolipid content of human non-seminomatous germ cell tumour cell lines correlates with their differentiation lineage. To analyse whether this reflects the situation in primary tumours, we studied five embryonal carcinomas, five yolk sac tumours and nine (mixed) non-seminomas, using thin-layer chromatography and carbohydrate immunostaining. We also analysed the glycolipid content of 19 seminomas to reveal their relationship with non-seminomas. Lactosylceramide (CDH) was detected in all embryonal carcinomas, but in fewer than half of the seminomas. Seminomas and embryonal carcinomas contained globoseries glycolipids, including globotriosylceramide (Gb3), globoside (Gb4), galactosy globoside (Gb5) and sialy1 galactosyl globoside (GL7). The lacto-series glycolipid Le(x) was found in all embryonal carcinomas, but only in one seminoma. Gangliosides GD3 and GT3 were detected in many seminomas, but rarely in embryonal carcinomas. Yolk sac tumours displayed a heterogeneous glycolipid profile. Compared with seminomas and pure embryonal carcinomas, differentiated non-seminomas had reduced levels of globo-series glycolipids, especially Gb3 and Gb5, whereas CDH, Le(x), GD3 and GT3 were found in the majority of cases. Thus, the glycolipid content of non-seminoma cell lines reflects the situation in primary tumours. Globo-series glycolipids are similarly expressed in seminomas and embryonal carcinomas. The expression of Gb3 and Gb5 is reduced in non-seminomas upon differentiation. Le(x) expression in non-seminomas, including embryonal carcinomas, allows discrimination from seminomas. Expression of gangliosides in seminomas might indicate their maturation from ganglioside-negative precursor cells. Reprogramming of these precursors would result in the formation of Le(x)-expressing embryonal carcinomas.     

Blood group-related antigens in human germ cell tumors

With the use of immunohistochemical techniques, seven mouse monoclonal antibodies and the lectin from Ulex europaeus, detecting blood group antigens of the ABH and Lewis systems, have been used to define the distribution of these antigenic structures in germ cell tumors. The reagents used recognize the following blood group antigens: A, B, H, Lewisa, Lewisb, X (Lewisx), Y (Lewisy), and type I precursor antigen. Tumors from 29 patients were studied. Tumors studied consisted of pure embryonal carcinoma for eight patients, pure yolk sac tumor for two patients, embryonal carcinoma plus yolk sac tumor in one patient, and yolk sac tumor plus seminoma in one patient. Also studied were nine classic seminomas and a group of six patients with tumors classified as seminomas that exhibited atypical histological features. One patient had an anaplastic carcinoma arising from the mediastinum which could not be conclusively identified as a germ cell tumor morphologically and was analyzed separately. All embryonal carcinomas and yolk sac tumors exhibited strong positivity for type I precursor structure as detected by the K-21 monoclonal antibody. In marked contrast, there was non staining in classic seminomas but heterogeneous staining in five of six atypical seminomas. The majority of embryonal carcinomas and all yolk sac tumors studied demonstrated strong positivity for blood group antigen H. For seminoma, however, only one of the atypical cases and two of the classic cases (occasional cells) stained for H. Focal expression of the Y antigen was identified in 5 of 17 seminomas and in the majority of embryonal carcinomas and yolk sac tumors. Two yolk sac tumors and two classic seminomas expressed blood group X. The remaining blood group antigens were not expressed by seminomas while they were variably expressed by embryonal carcinoma and yolk sac tumors. These data suggest that K-21 and blood group antigen H may be distinguishing markers of nonseminomatous germ cell tumor versus seminoma. If so, it is possible that the heterogeneous expression of blood group substances in seminomas with atypical histologies is an indication of differentiation towards nonseminomatous germ cell tumor.     

Platinum-based chemotherapy of primary extragonadal germ cell tumours: the Hellenic Cooperative Oncology Group experience.

Extragonadal germ cell tumours (EGCT) are uncommon, most frequently arise in the mediastinum and retroperitoneum and have variable responses to platinum-based chemotherapy. A retrospective analysis was performed on 38 patients with EGCT treated with cisplatin-based (CDDP) or carboplatin-based (CBDCA) chemotherapy between 1984 and 1998. Twenty-four patients had nonseminomatous germ cell tumours (NSGCT) and 14 seminoma. Twenty-two tumours arose in the mediastinum (13 nonseminomas, 9 seminomas) and 16 in the retroperitoneum (11 NSGCT, 5 seminomas). Initial surgery included complete resection in 1 patient, biopsy in 27 patients and debulking surgery in 10 patients. Complete response rates with chemotherapy +/- surgery were as follows: mediastinum 14 of 21 (66.66%) patients (8 of 12-75% NSGCT, 6 of 9-66.66% seminomas) and retroperitoneum 14 of 16 (87.5%) patients (9 of 11-81.81% NSGCT, 5 of 5-100% seminomas). One patient who underwent complete resection of a mediastinal malignant teratoma combined, received PVB chemotherapy on an adjuvant basis and remains alive and disease-free. Three additional seminoma patients who achieved partial response after chemotherapy remain alive and disease-free following mediastinal radiotherapy. All 14 patients with extragonadal seminomas remain alive with no evidence of disease at a median follow-up of 49 months (range 7-164), giving an overall survival of 100%. Nine of 13 (69.23%) patients with mediastinal NSGCT are long-term disease-free at a median follow-up of 43.5 months (range 7-152). Nine of 11 (81.81%) patients with retroperitoneal NSGCT remain alive and disease-free at a median follow-up of 56 months (range 14-110). Complete surgical resection of residual mass was undertaken in 10 patients (3 seminomas, 7 nonseminomas). The histology revealed necrosis/fibrosis in 6 patients (3 seminomas, 3 NSGCT) and viable cancer in 4 patients. Patients who had viable malignant cells in the resected specimens received two more courses of VelP chemotherapy. None of our patients had relapsed at the time of this analysis. None of our 6 patients who underwent testicular biopsy (1 patient) or orchiectomy (5 patients) due to suspicious ultrasound of the testis were found to have testicular tumour or fibrotic scar. In conclusion, this retrospective analysis showed significant responses in patients with either mediastinal or retroperitoneal NSGCT treated with CDDP- or CBDCA-based chemotherapy +/- surgery. All patients with extragonadal seminomas remain alive with no evidence of disease, regardless of the site at presentation.     

Multimodality treatment of malignant germ cell tumours of the mediastinum

Of 15 patients with malignant germ cell tumours of the mediastinum, 9 patients had pure seminomas and 6 had non-seminomas. Resection was radical in only 4 non-seminomas, 1 of which was resected after chemotherapy; radiotherapy was delivered to all seminoma patients as sole therapy (2 patients) or as part of combined modality therapy. All patients with non-seminomatous tumours underwent chemotherapy (cisplatin-based combination). Therapy was generally well tolerated, but 1 seminoma patient died of sepsis. Chemotherapy achieved a 71% complete response rate in pure seminoma patients and a 33% complete response rate in non-seminoma patients. 53% of patients are alive and free of disease beyond 36 months from start of any treatment. Pure seminoma patients survived longer than non-seminoma patients (3 and 5 year survivals were 67% and 33%, respectively). Although cisplatin-based chemotherapy is highly effective in pure seminomas and also in non-seminomas, a better therapeutic approach is needed in non-seminomas.     

Teratocarcinoma stem cells

Human teratocarcinomas or mixed germ cell tumours are histologically composed of diverse tissues corresponding to somatic and extraembryonic (trophoblastic and yolk sac) like cells, as well as malignant stem cells. In typical teratocarcinomas these stem cells correspond to embryonal carcinoma cells, ie developmentally pluripotent cells equivalent to embryonic cells from the early stages of development. These cells have the capacity to differentiate and give rise to non-proliferating terminally differentiated tissue. Occasionally embryonal carcinoma cells can give rise to more differentiated stem cells which have the phenotype and the restricted developmental potential of choriocarcinoma and yolk sac carcinoma cells, or less commonly to somatic cell malignancies, indistinguishable from typical carcinomas, sarcomas, melanoma or lymphomas. Malignant transformation of benign somatic tissues in teratomas can also give rise to malignant stem cells, which all have a somatic cell phenotype. The biology and the clinical presentation as well as the response to chemotherapy of germ cell tumours depend on the nature of stem cells that form their proliferative compartment and account for the malignancy of these tumours.     

Protein overexpression and gene amplification of epidermal growth factor receptor in adult testicular germ cell tumors: Potential role in tumor progression

Little is known about the pathologic significance of epidermal growth factor receptor (EGFR) expression in malignant testicular germ cell tumors (TGCTs) in adults. From the primary tumor sites of a cohort of 110 TGCT cases, we obtained 209 histologically distinct components: 53 intratubular germ cell neoplasia unclassified (IGCNU) lesions, 83 seminomas (66 pure‐form seminomas and 17 seminoma components in the mixed‐form with nonseminomatous TGCTs), 27 embryonal carcinomas, eight choriocarcinomas, 18 yolk sac tumors, and 20 immature teratomas. Samples were analyzed for expression of EGFR protein and EGFR gene amplification by immunohistochemistry and fluorescence in situ hybridization (FISH), respectively. Overexpression of the EGFR protein was detected in 28% of seminomas (27% in the pure‐form and 29% in the mixed‐form), 11% of embryonal carcinomas, 88% of choriocarcinomas, 44% of yolk sac tumors, and none of the IGCNU lesions or immature teratomas. A higher copy number (≥4 copies per cell) and amplification of the EGFR gene were detected in 20% and 10% of seminomas, 13% and 0% of embryonal carcinomas, 71% and 60% of choriocarcinomas, 15% and 8% of yolk sac tumors, and none of the IGCNU lesions or immature teratomas, respectively. Both higher copy number and amplification of the EGFR gene were positively correlated with immunohistochemical overexpression of EGFR protein (each P < 0.0001). These results suggest that overexpression of EGFR protein and increased copy number or amplification of the EGFR gene occur relatively frequently in primary TGCTs, and may play roles in the formation of invasive cancer and in the progression, especially morphological evolution, of tumors. (Cancer Sci 2010)     

Antikeratin antibodies in tumor diagnosis. Distinction between seminoma and embryonal carcinoma

The authors investigated the presence and distribution of keratin in germ cell tumors using a rabbit-anti-keratin antiserum and a monoclonal antikeratin antibody--which is specific for keratin classes of 40, 50, and 56.5 kdaltons--by various immunohistochemical methods on frozen sections, alcohol-fixed, and formalin-fixed paraffin-embedded tissues. Thirty-four germ cell tumors were studied. These were the following: 18 seminomas, 10 embryonal carcinomas, 2 teratocarcinomas, 3 yolk sac tumors and 1 choriocarcinoma. All seminomas, including four poorly differentiated (so-called anaplastic seminomas), gave negative results, regardless of the method employed. Embryonal carcinoma, the epithelial component of the teratocarcinoma, the yolk sac tumors, and choriocarcinoma were at least focally positive for keratin. The monoclonal antibody provided a cleaner background and stronger staining than the rabbit-anti-total-human-epidermal-keratin antibody. Best results were obtained from fresh-frozen sections or alcohol-fixed, paraffin-embedded materials. Formalin-fixed, nonseminomatous tumors, when predigested with trypsin and incubated overnight with primary antibody, gave no false-negative results but staining was often focal. The authors' results agree with the reported absence of detectable keratin in primordial germ cells of the normal testis, and with prevailing concepts of the histogenesis of germ cell tumors. These results indicate that the presence or absence of keratin by immunocytochemical methods can be helpful in distinguishing seminoma from embryonal carcinoma.     

Malignant ovarian tumours in childhood in Britain, 1962-78

The files of the Childhood Cancer Research Group and of the Oxford Survey of Childhood Cancers were scrutinized for all the ovarian neoplasms registered in England, Scotland and Wales in children under age 15 years throughout the period 1962-78. Among 172 cases confirmed as malignant ovarian tumours, 145 (84%) were tumours of germ cell origin (54 dysgerminomas, 36 malignant teratomas, 26 endodermal sinus tumours, 4 embryonal carcinomas, 2 pure choriocarcinomas, 20 mixed germ cell neoplasms, 3 gonadoblastomas), 13 (8%) were epithelial carcinomas (3 serous or undifferentiated, 10 mucinous), 9 (5%) were sex-cord stromal tumours (3 granulosa cell, 3 Sertoli-Leydig, 3 unclassified) and 5 (3%) were other miscellaneous tumour types. Less than 10% of the neoplasms occurred at age less than 5 years, approximately 20% from 5-9, and greater than 70% from 10-14 years. Germ cell neoplasms of greater malignancy (immature teratomas, endodermal sinus tumours) occurred in a significantly higher proportion at younger age (less than 10 years) than dysgerminomas (P = 0.01). The overall incidence (approximately 1.7 cases per 10(6) per annum) did not show any noticeable trend over the 17-year period considered. The clustering of two confined cases and, possibly, a third case, of germ cell neoplasms in three generations of the same family pointed to a genetic component in the aetiology of some of these neoplasms. A large number of sex related and mental or neurological abnormalities was also reported in case children. The 10-year survival rates, determined by the life-table method were: epithelial carcinomas 73%, sex-cord stromal tumours 44%, dysgerminomas 73%, malignant teratomas 33%, endodermal sinus tumours 39%, embryonal carcinomas 25%, other germ cell neoplasms 30% and gonadoblastomas 100%. Apart from cell-type, factors associated with prognosis were clinical stage (in all types), size and degree of histological differentiation (in malignant teratomas, but only when stage was not allowed for). The adoption of efficacious polychemotherapy regimens completely changed the prognosis of germ cell tumours other than dysgerminomas (from 29% to greater than 85% disease-free survivors in the present series).     

Carcinoma in situ testis, the progenitor of testicular germ cell tumours: a clinical review.

Testicular germ cell tumours (TGCT), including seminomas, embryonal carcinomas, teratomas and yolk sac tumours, have a common precursor, the carcinoma in situ (CIS) cell. Recent gene expression studies displaying close similarity of CIS cells to embryonic stem cells support the longstanding theory that CIS most likely originates in utero from fetal gonocytes. The clinical association between the testicular dysgenesis syndrome components (TGCT, cryptorchidism, genital malformations, some forms of decreased spermatogenesis) also implies a prenatal origin. Despite high cure rates of TGCT, efforts should be made to obtain diagnosis at the CIS stage, as intervention is possible before an invasive tumour develops, thus reducing the necessity for intensive therapy. CIS may be suspected in patients with an assumed extragonadal GCT or cryptorchidism, and in intersex patients and selected cases with infertility (presenting with atrophic testes and ultrasonic microlithiasis). Surgical testicular biopsy seems the only reliable diagnostic method. The management of choice of unilateral CIS is orchidectomy, or localised irradiation in bilateral cases. At least 5% of TGCT patients present with contralateral CIS; therefore, contralateral biopsy is recommended at the time of orchidectomy. Further research is warranted to identify causal factors explaining the increasing incidence of TGCT and to obtain a method of non-invasive CIS detection.     

Testicular Germ Cell Tumours in Denmark 1976-1980 Pathology of 1058 Consecutive Cases

In the first five-year period of the Danish Testicular Carcinoma Study (DATECA) 1058 consecutive testicular germ cell tumours were examined. Of these, 554 were seminomas comprising 515 of typical type, 26 anaplastic and 13 spermatocytic; 497 were non-seminomas comprising 145 pure tumours and 352 mixed tumours of various types. Among the various subtypes of non-seminomas embryonal carcinoma (EC) was recorded in 87 per cent, endodermal sinus tumour (yolk sac tumour; EST) in 22 per cent, teratoma (T) in 55 per cent and choriocarcinoma (CC) in 17 per cent. Only very few tumours were pure EST or pure CC. Five tumours were recorded as 'others or uncertain'. The tumours were graded with regard to various histologic features. Moderate and severe necrosis, bleeding, and a large number of mitoses were significantly more frequent in non-seminomas. The presence of tumour tissue at the resection margin was also more frequent in non-seminomas. Tumours with a largest diameter of less than 2.5 cm had already caused metastases in 16 per cent of the seminomas and 29 per cent of the non-seminomas. Increasing size of the tumours was associated with increasing frequency of metastatic disease but this association was not directly proportional. Distribution of the various histologic types according to the stage of disease varied. Thus, 78 per cent of the seminomas presented in stage 1 while 54 per cent of the non-seminomas had localized disease. Anaplastic seminomas were distributed similarly to the non-seminomas while all spermatocytic seminomas, with one exception, were recorded as stage I. Of non-seminomatous subtypes pure EC was associated with the highest frequency of stage III, followed by mixed tumours containing CC components. Although the present series is large the heterogeneity of germ cell tumours demands further investigation of larger numbers to confirm some of the findings.     

SALL4 is a novel sensitive and specific marker for metastatic germ cell tumors,with particular utility in detection of metastatic yolk sac tumors

BACKGROUND:

The correct diagnosis of metastatic germ cell tumors is critical, because these tumors can be effectively treated and are even cured with modern therapy. Their histopathologic diagnosis can be challenging without immunohistochemical markers, which currently have limitations. SALL4 is a novel stem cell marker essential to maintain pluripotency and self‐renewal of embryonic stem cells. In the current study, the authors investigated the utility of SALL4 as a potential diagnostic marker for metastatic germ cell tumors.

METHODS:

Ninety metastatic germ cell tumors from testis, ovary, and extragonadal sites were stained with a monoclonal SALL4 antibody. In addition, 170 metastatic nongerm cell malignancies, including 158 carcinomas (6 head and neck, 8 thyroid, 12 lung, 8 breast, 7 hepatocellular, 3 cholangiocarcinomas, 2 ampullary, 10 pancreatic, 18 gastric, 15 esophageal, 10 renal cell, 10 urothelial, 12 prostatic, 18 ovarian, 6 uterine, and 13 colonic) and 12 melanomas, were also stained to test SALL4 specificity.

RESULTS:

All 22 seminomas, 7 dysgerminomas, 22 embryonal carcinomas, and 14 of 15 yolk sac tumors displayed strong and diffuse SALL positivity in >90% of tumor cells (80% of tumor cells were strongly positive in the remaining yolk sac tumor). Five of 7 choriocarcinomas and 9 of 18 teratomas were also variably positive for SALL4. In contrast, only 10 (esophageal, gastric, and colonic adenocarcinomas) of 170 metastatic somatic tumors demonstrated focally weak SALL4 reactivity (<25% tumor cells).

CONCLUSIONS:

SALL4 is a novel sensitive and highly specific marker for metastatic germ cell tumors, and is particularly useful for detecting metastatic yolk sac tumors. Cancer 2009. © 2009 American Cancer Society.     

Immunohistochemical localisation of alpha-fetoprotein (AFP) in germ cell tumours: evidence for AFP production by tissues different from endodermal sinus tumour

20 germ cell tumours have been studied with respect to the presence of alpha-fetoprotein (AFP), using the peroxidase-antiperoxidase (PAP) technique. 6 out of 20 tumours contained elements of endodermal sinus tumour (EST) and were AFP positive. 16 tumours were diagnosed either as pure embryonal carcinomas (6) or as mixed germ cell tumours, containing elements of embryonal carcinoma (10). In 3 of these 16 tumours AFP was localised definitely in the embryonal carcinoma cells; in an additional 6, AFP was also detected but it could not be decided whether AFP was present in embryonal carcinoma cells or in EST cells during early differentiation. In 2 of 7 immature teratomas, AFP was shown to be present in cylindric epithelia. All seminomas (4) studied were AFP-negative. These results show that AFP, which occurs regularly in EST, may also be present in embryonal carcinomas as well as in immature teratomas. Thus, it seems that the immunohistochemical demonstration of AFP by the PAP technique is a suitable method of identifying late stages of embryonal carcinoma or early stages of endodermal sinus tumour during the process of differentiation.     

The management of stage I nonseminomatous testicular germ cell tumors

Testicular germ cell tumors represent the most common malignancies in young males; 70% of patients with seminomas and 50% of those with nonseminomatous germ cell tumors (NSGCT) have clinical stage I at diagnosis. Lymphovascular invasion, embryonal-cell carcinoma component, absence of yolk sac histology and MIB1 proliferation rate represent predictors of micrometastatic diseasein stage I NSGCT. Therapeutic options following orchiectomy in patients with stage I NSGCT comprise nerve-sparing retroperitoneal lymph node dissection, surveillance or adjuvant cisplatin-based chemotherapy. All available treatment modalities produce excellent results, with a long-term survival of almost 100%. Consequently, therapy-induced toxicity is an important concern in the management of these patients. An individually tailored approach that takes into account the prognostic factor profile as well as the patient's preferences and their ability to comply with each one of the modalities is the key to the management of stage I testicular cancer.     

Primary malignant mediastinal germ cell tumours: A literature review and a study of 18 cases

From 1957 to 1992, 18 cases of primary mediastinal germ cell tumours were referred to the Peter MacCallum Cancer Institute (PMCI). Six were seminomas, six were mixed germ cell tumours, two were embryonal cell carcinomas, three were teratocarcinomas and one was labelled an ‘anaplastic germ cell tumour’. Two of the 18 patients were female. For seminomas, surgical (and in one case chemotherapeutic) debulking, followed by radiotherapy produced the best results. Mediastinal doses ranged from 30 to 40 Gy. Local control was achieved in those patients receiving mediastinal radiotherapy. Four patients currently survive disease-free. The non-seminomatous germ cell tumours showed a significantly poorer survival, and only two of 12 patients remain alive in remission at 110 and 130 months after diagnosis. Survival has been updated as of November 1997. Attention is focused on the anterior position of the primary germ cell tumours in the mediastinum. A review of the literature up to and including 1997 is presented.     

Ultrastructural studies of xenografted human germ cell tumors

Xenografts have been established in immune-suppressed mice from three embryonal cell carcinomas, two yolk sac carcinomas, and a 'seminoma-like' tumor that produces alphafetoprotein. The ultrastructural features of these xenografts have been studied in detail and compared with human germ cell tumors removed from patients. A spectrum of ultrastructural differentiation has been demonstrated for tumors of the same histologic classification (embryonal cell carcinoma) and within individual tumors. Cells with ultrastructural appearances intermediate between seminoma and yolk sac carcinoma and between embryonal cell and yolk sac carcinoma have been demonstrated, and their potential implications for tumor histogenesis are discussed.     

Primary Malignant Germ Cell Tumours of the Mediastinum: Results of Multimodality Treatment

Primary malignant mediastinal germ cell tumours are rare and considered to have poorer prognosis compared with those arising from gonads. Eighteen patients with primary mediastinal germ cell tumour were treated over an 11-year period; 9 had seminoma and 9 non-seminoma. Eight patients, 4 each with seminoma and non-seminoma underwent initial tumour excision and the rest had biopsy only. All patients received cisplatin-based chemotherapy. All patients with seminoma received consolidation radiotherapy to mediastinum. Three patients with non-seminoma received radiotherapy following partial response. All 9 patients with seminoma achieved complete response at the end of chemotherapy. Two patients with NSGCT had complete response to chemotherapy, 5 partial response and 2 no response. Two patients who underwent resection of the residual tumour mass are surviving free of disease. Addition of radiotherapy or second-line chemotherapy did not bring about any added response in partial and non-responders. Nine out of 9 patients with seminoma and 4/9 with non-seminoma are surviving disease-free at a median follow-up of 48 months (range 16-153 months). Mediastinal seminoma has excellent prognosis with cisplatin combination chemotherapy, whereas non-seminoma carries poor prognosis, and aggressive chemotherapy with resection of residual masses may improve the outcome. The role of additional radiotherapy and initial tumour debulking needs further evaluation.     

Involvement of dysadherin and E-cadherin in the development of testicular tumours

Testicular neoplasms are comprised of a variety of histologically different forms, and their pathogenesis has not been elucidated. Dysadherin is a recently described cell membrane glycoprotein, which has an anticell-cell adhesion function and downregulates E-cadherin. In this study, we examined immunohistochemically the expression of E-cadherin and dysadherin in 120 testicular neoplasms (37 seminomas-26 classic, five spermatocytic and six anaplastic-, 45 embryonal carcinomas, 10 mixed germ cell tumours, two yolk sac tumours, 10 mature and eight immature teratomas and eight non-Hodgkin B-cell lymphomas), clinical stage I. The intensity, the expression pattern and the percentage of neoplastic cell staining was recorded and correlated with the histologic type and vascular/lymphatic invasion. Dysadherin was not expressed in non-neoplastic germ cells, neither in CIS/ITGCNU, but it was highly expressed in all types of germ cell tumours, that demonstrated either embryonic phenotype or somatic differentiation, in most terminally differentiated neoplasms, and in all lymphomas. Dysadherin expression did not correlate with vascular invasion. Increased dysadherin expression was correlated with aberrant E-cadherin expression in most tumours. In 17% of embryonal carcinomas colocalisation of dysadherin and membranous E-cadherin staining was noted. This is the first report on dysadherin expression and its association with E-cadherin in testicular tumours. Since dysadherin is not normally expressed in non-neoplastic testis, it is conceivable that it plays a role in the neoplastic transformation of germ cells. In testicular tumours, as in other neoplasms, dysadherin downregulates E-cadherin expression, at least in part.