Wilms Tumor With Raised Serum Alpha-Fetoprotein: Highlighting the Need for Novel Circulating Biomarkers.

Wilms tumor (WT) is the commonest cause of renal cancer in children. In Europe, a diagnosis is made for most cases on typical clinical and radiological findings, prior to pre-operative chemotherapy. Here, we describe a case of a young boy presenting with a large abdominal tumor, associated with raised serum alpha-fetoprotein (AFP) levels at diagnosis. Given the atypical features present, a biopsy was taken, and histology was consistent with WT, showing triphasic WT, with epithelial, stromal, and blastemal elements present, and positive WT1 and CD56 immunohistochemical staining. During pre-operative chemotherapy, serial serum AFP measurements showed further increases, despite a radiological response, before a subsequent fall to normal following nephrectomy. The resection specimen was comprised of ~55% and ~45% stromal and epithelial elements, respectively, with no anaplasia, but immunohistochemistry using AFP staining revealed positive mucinous intestinal epithelium, consistent with the serum AFP observations. The lack of correlation between tumor response and serum AFP levels in this case highlights a more general clinical unmet need to identify WT-specific circulating tumor markers.

Targeting oncogenic microRNAs from the miR-371~373 and miR-302/367 clusters in malignant germ cell tumours causes growth inhibition through cell cycle disruption.

BACKGROUND: MiR-371~373 and miR-302/367 cluster over-expression occurs in all malignant germ cell tumours (GCTs), regardless of age (paediatric/adult), site (gonadal/extragonadal), or subtype [seminoma, yolk sac tumour (YST), embryonal carcinoma (EC)]. Six of eight microRNAs from these clusters contain the seed sequence 'AAGUGC', determining mRNA targeting. Here we sought to identify the significance of these observations by targeting these microRNAs functionally. METHODS: We targeted miR-371~373 and/or miR-302/367 clusters in malignant GCT cell lines, using CRISPR-Cas9, gapmer primary miR-302/367 transcript inhibition, and peptide nucleic acid (PNA) or locked nucleic acid (LNA)-DNA inhibition targeting miR-302a-d-3p, and undertook relevant functional assays. RESULTS: MiR-302/367 cluster microRNAs made the largest contribution to AAGUGC seed abundance in malignant GCT cells, regardless of subtype (seminoma/YST/EC). Following the unsuccessful use of CRISPR-Cas9, gapmer, and PNA systems, LNA-DNA-based targeting resulted in growth inhibition in seminoma and YST cells. This was associated with the de-repression of multiple mRNAs targeted by AAGUGC seed-containing microRNAs, with pathway analysis confirming predominant disruption of Rho-GTPase signalling, vesicle organisation/transport, and cell cycle regulation, findings corroborated in clinical samples. Further LNA-DNA inhibitor studies confirmed direct cell cycle effects, with an increase of cells in G0/G1-phase and a decrease in S-phase. CONCLUSION: Targeting of specific miR-371~373 and miR-302/367 microRNAs in malignant GCTs demonstrated their functional significance, with growth inhibition mediated through cell cycle disruption.

Imaging response assessment for CNS germ cell tumours: consensus recommendations from the European Society for Paediatric Oncology Brain Tumour Group and North American Children's Oncology Group.

Homogeneous and common objective disease assessments and standardised response criteria are important for better international clinical trials for CNS germ cell tumours. Currently, European protocols differ from those of North America (the USA and Canada) in terms of criteria to assess radiological disease response. An international working group of the European Society for Paediatric Oncology Brain Tumour Group and North American Children's Oncology Group was therefore established to review existing literature and current practices, identify major challenges regarding imaging assessment, and develop consensus recommendations for imaging response assessment for patients with CNS germ cell tumours. New clinical imaging standards were defined for the most common sites of CNS germ cell tumour and for the definition of locoregional extension. These new standards will allow the evaluation of response to therapy in patients with CNS germ cell tumours to be more consistent, and facilitate direct comparison of treatment outcomes across international studies.

The NHS England 100,000 Genomes Project: feasibility and utility of centralised genome sequencing for children with cancer.

BACKGROUND: Whole-genome sequencing (WGS) of cancers is becoming an accepted component of oncological care, and NHS England is currently rolling out WGS for all children with cancer. This approach was piloted during the 100,000 genomes (100 K) project. Here we share the experience of the East of England Genomic Medicine Centre (East-GMC), reporting the feasibility and clinical utility of centralised WGS for individual children locally. METHODS: Non-consecutive children with solid tumours were recruited into the pilot 100 K project at our Genomic Medicine Centre. Variant catalogues were returned for local scrutiny and appraisal at dedicated genomic tumour advisory boards with an emphasis on a detailed exploration of potential clinical value. RESULTS: Thirty-six children, representing one-sixth of the national 100 K cohort, were recruited through our Genomic Medicine Centre. The diagnoses encompassed 23 different solid tumour types and WGS provided clinical utility, beyond standard-of-care assays, by refining (2/36) or changing (4/36) diagnoses, providing prognostic information (8/36), defining pathogenic germline mutations (1/36) or revealing novel therapeutic opportunities (8/36). CONCLUSION: Our findings demonstrate the feasibility and clinical value of centralised WGS for children with cancer. WGS offered additional clinical value, especially in diagnostic terms. However, our experience highlights the need for local expertise in scrutinising and clinically interpreting centrally derived variant calls for individual children.

Advancing clinical and translational research in germ cell tumours (GCT): recommendations from the Malignant Germ Cell International Consortium.

Germ cell tumours (GCTs) are a heterogeneous group of rare neoplasms that present in different anatomical sites and across a wide spectrum of patient ages from birth through to adulthood. Once these strata are applied, cohort numbers become modest, hindering inferences regarding management and therapeutic advances. Moreover, patients with GCTs are treated by different medical professionals including paediatric oncologists, neuro-oncologists, medical oncologists, neurosurgeons, gynaecological oncologists, surgeons, and urologists. Silos of care have thus formed, further hampering knowledge dissemination between specialists. Dedicated biobank specimen collection is therefore critical to foster continuous growth in our understanding of similarities and differences by age, gender, and site, particularly for rare cancers such as GCTs. Here, the Malignant Germ Cell International Consortium provides a framework to create a sustainable, global research infrastructure that facilitates acquisition of tissue and liquid biopsies together with matched clinical data sets that reflect the diversity of GCTs. Such an effort would create an invaluable repository of clinical and biological data which can underpin international collaborations that span professional boundaries, translate into clinical practice, and ultimately impact patient outcomes.

Vinblastine monotherapy induction prior to radiotherapy for patients with intracranial germinoma during the COVID-19 pandemic.

BACKGROUND: Patients with localized intracranial germinoma have excellent survival. Reducing treatment burden and long-term sequelae is a priority. Intensive inpatient chemotherapy (e.g., carboPEI = carboplatin/etoposide/ifosfamide) has been effectively employed to reduce radiotherapy treatment volume/dose. Outpatient-based carboplatin monotherapy is associated with excellent outcomes in metastatic testicular seminoma (an identical pathology), and successful vinblastine monotherapy induction (with 77% tumor volume reduction after just two weekly vinblastine doses) has recently been reported in an intracranial germinoma patient. METHODS: Adapted UK guidelines for germ cell tumor management were distributed during the COVID-19 pandemic, including nonstandard treatment options to reduce hospital visits and/or admissions. This included vinblastine monotherapy for intracranial germinoma (6 mg/m2 intravenously, or 4 mg/m2 for moderate count suppression, delivered weekly). We describe two such patients treated using this approach. RESULTS: A 30-year-old male with a localized pineal tumor received 12-week vinblastine induction, with >60% volume reduction, prior to definitive radiotherapy. A 12-year-old female with a metastatic suprasellar tumor and progression at all sites of disease whilst awaiting proton radiotherapy received two vinblastine doses with good early response, including 36% primary tumor volume reduction. The patients tolerated vinblastine well. CONCLUSION: Patients with intracranial germinoma have excellent outcomes, and reduction of late effects remains a priority. The description of vinblastine monotherapy in these intracranial germinoma patients warrants further exploration.

Outcomes of adolescent males with extracranial metastatic germ cell tumors: A report from the Malignant Germ Cell Tumor International Consortium.

BACKGROUND: Adolescents with extracranial metastatic germ cell tumors (GCTs) are often treated with regimens developed for children, but their clinical characteristics more closely resemble those of young adult patients. This study was designed to determine event-free survival (EFS) for adolescents with GCTs and compared them with children and young adults. METHODS: An individual patient database of 11 GCT trials was assembled: 8 conducted by pediatric cooperative groups and 3 conducted by an adult group. Male patients aged 0 to 30 years with metastatic, nonseminomatous, malignant GCTs of the testis, retroperitoneum, or mediastinum who were treated with platinum-based chemotherapy were included. The age groups were categorized as children (0 to <11 years), adolescents (11 to <18 years), and young adults (18 to ≤30 years). The study compared EFS and adjusted for risk group by using Cox proportional hazards analysis. RESULTS: From a total of 2024 individual records, 593 patients met the inclusion criteria: 90 were children, 109 were adolescents, and 394 were young adults. The 5-year EFS rate was lower for adolescents (72%; 95% confidence interval [CI], 62%-79%) than children (90%; 95% CI, 81%-95%; P = .003) or young adults (88%; 95% CI, 84%-91%; P = .0002). The International Germ Cell Cancer Collaborative Group risk group was associated with EFS in the adolescent age group (P = .0020). After adjustments for risk group, the difference in EFS between adolescents and children remained significant (hazard ratio, 0.30; P = .001). CONCLUSIONS: EFS for adolescent patients with metastatic GCTs was similar to that for young adults but significantly worse than for that children. This finding highlights the importance of coordinating initiatives across clinical trial organizations to improve outcomes for adolescents and young adults. LAY SUMMARY: Adolescent males with metastatic germ cell tumors (GCTs) are frequently treated with regimens developed for children. In this study, a large data set of male patients with metastatic GCTs across different age groups has been built to understand the outcomes of adolescent patients in comparison with children and young adults. The results suggest that adolescent males with metastatic GCTs have worse results than children and are more similar to young adults with GCTs. Therefore, the treatment of adolescents with GCTs should resemble therapeutic approaches for young adults.

Recurrent ovarian immature teratoma in a 12-year-old girl: Implications for management.

Immature teratomas (IT) are rare and recurrences uncommon. A 12-year-old female with grade 3 (high-grade) ovarian IT underwent surgical resection but experienced early recurrences; the first was treated with surgery but the second was metastatic and managed with chemotherapy, resulting in growing-teratoma-syndrome and need for further surgery. She now remains well in uneventful clinical follow-up. We believe chemotherapy could be reserved for very carefully selected recurrent IT cases, which may alter the natural history of disease.

Is carboplatin-based chemotherapy as effective as cisplatin-based chemotherapy in the treatment of advanced-stage dysgerminoma in children, adolescents and young adults?

OBJECTIVE: Dysgerminoma is the most common malignant ovarian germ cell tumor (GCT) with peak incidence during adolescence and young adulthood. Current standard of care for patients with disease that has spread outside of the ovary (advanced-stage) utilizes platin-based chemotherapy regimens. The study objective was to compare clinical outcomes between platin-based (carboplatin versus cisplatin) strategies across all age groups (children < 11 years (y), adolescents = 11-25 y and young adult women > 25 y) for advanced-stage dysgerminoma. METHODS: The Malignant Germ Cell Tumor International Consortium (MaGIC) pooled data from six GCT trials (3 = pediatric, 3 = adult) conducted internationally by pediatric and gynecologic oncology clinical trial organizations (CTOs) between 1983 and 2009. Newly diagnosed patients, with advanced-stage (FIGO IC-IV) dysgerminoma, who received either carboplatin- or cisplatin-based chemotherapy were eligible for analysis. RESULTS: 126 eligible patients were identified; 56 patients (38 = pediatric, 18 = adult) received carboplatin-based and 70 patients (50 = pediatric, 20 = adult) received cisplatin-based chemotherapy. Mean age was 20 y (range = 6-46 y). The median follow-up was 10.3 y (range = 0.17-21.7 y). The five-year event-free survival (EFS5) and overall survival (OS5) was 0.94 (95%CI, 0.88-0.97) and 0.96 (95%CI, 0.91-0.99) respectively. Survival outcomes were comparable between carboplatin-(EFS5 = 0.96 (95%CI, 0.85-0.99), OS5 = 0.96 (95%CI, 0.85-0.99)) and cisplatin-(EFS5 = 0.93 (95%CI, 0.83-0.97), OS5 = 0.96 (95%CI, 0.87-0.99)) based regimens. Across three age groups, comparison of the EFS5 (<11 y = 0.1, 11-25 y = 0.91 (95%CI, 0.82-0.96), >25 y = 0.97 (95%CI, 0.81-0.99)) and OS5 (<11 y = 0.1, 11-25 y = 0.95 (95%CI, 0.87-0.99), >25 y = 0.97 (95%CI, 0.81-0.99)) did not demonstrate any statistically significant differences in outcomes. CONCLUSIONS: Patients diagnosed with dysgerminoma have an excellent OS, across all ages, even in the context of metastatic disease. Data from three large CTOs supports the investigation of carboplatin-based regimens in the frontline treatment of all patients with advanced-stage dysgerminoma to minimize treatment-related toxicities.

Treatment and outcomes of UK and German patients with relapsed intracranial germ cell tumors following uniform first-line therapy.

We aimed to retrospectively assess treatments/outcomes, including the value of high-dose-chemotherapy and autologous-stem-cell-rescue (HDC + AuSCR) and re-irradiation, in a large, European patient-cohort with relapsed intracranial germ-cell-tumors (GCTs) receiving uniform first-line therapy, including radiotherapy as standard-of-care. Fifty-eight UK/German patients (48 male/10 female) with relapsed intracranial-GCTs [13 germinoma/45 non-germinomatous GCT (NGGCT)] treated 1996-2010 as per the SIOP-CNS-GCT-96 protocol were evaluated. For germinoma, six patients relapsed with germinoma and five with NGGCT (one palliative, one teratoma patient excluded). Five-year overall-survival (OS) for the whole-group (n = 11) was 55%. Four of six germinoma relapses and two of five relapsing with NGGCT were salvaged; patients were salvaged with either standard-dose-chemotherapy (SDC) and re-irradiation or HDC + AuSCR with/without re-irradiation. Of 45 relapsed NGGCT patients, 13 were excluded (three non-protocol adherence, five teratoma, five palliation). Five-year OS for the remaining 32 relapsed malignant NGGCT patients treated with curative intent was 9% (95%CI: 2-26%). By treatment received, 5-year OS for the 10 patients receiving SDC and 22 patients treated with intention for HDC + AuSCR was 0% (0-0%) and 14% (3-36%), respectively. The three relapsed NGGCT survivors had raised HCG markers alone; two received additional irradiation. Patients with relapsed germinoma had better 5-year OS than those with relapsed NGGCT (55 vs. 9%; p = 0.007). Patients with relapsed germinoma were salvaged both with SDC and re-irradiation or HDC + AuSCR with/without re-irradiation; both represent valid treatment options. Outcomes for malignant relapse following initial diagnosis of NGGCT were exceptionally poor; the few survivors received thiotepa-based HDC + AuSCR, which is a treatment option at first malignant relapse for such patients, with further surgery/irradiation where feasible.

Paediatric extracranial germ-cell tumours.

Management of paediatric extracranial germ-cell tumours carries a unique set of challenges. Germ-cell tumours are a heterogeneous group of neoplasms that present across a wide age range and vary in site, histology, and clinical behaviour. Patients with germ-cell tumours are managed by a diverse array of specialists. Thus, staging, risk stratification, and treatment approaches for germ-cell tumours have evolved disparately along several trajectories. Paediatric germ-cell tumours differ from the adolescent and adult disease in many ways, leading to complexities in applying age-appropriate, evidence-based care. Suboptimal outcomes remain for several groups of patients, including adolescents, and patients with extragonadal tumours, high tumour markers at diagnosis, or platinum-resistant disease. Survivors have significant long-term toxicities. The challenge moving forward will be to translate new insights from molecular studies and collaborative clinical data into improved patient outcomes. Future trials will be characterised by improved risk-stratification systems, biomarkers for response and toxic effects, rational reduction of therapy for low-risk patients and novel approaches for poor-risk patients, and improved international collaboration across paediatric and adult cooperative research groups.

Is adjuvant chemotherapy indicated in ovarian immature teratomas? A combined data analysis from the Malignant Germ Cell Tumor International Collaborative.

BACKGROUND: There is a debate regarding the management of ovarian immature teratomas (ITs). In adult women, postoperative chemotherapy is standard except for stage I, grade 1 disease, whereas surgery alone is standard in pediatric patients. To determine the role of chemotherapy, a pooled analysis of pediatric and adult clinical trials was conducted. METHODS: Data from 7 pediatric trials and 2 adult trials were merged in the Malignant Germ Cell International Collaborative data set. Four trials included patients with newly diagnosed pure ovarian ITs and were selected (Pediatric Oncology Group/Children's Cancer Group Intergroup Study (INT 0106), Second UKCCSG Germ Cell Tumor Study (GC2), Gynecologic Oncology Group (GOG 0078 and GOG 0090). Adult and pediatric trials were analyzed separately. The primary outcome measures were event-free survival (EFS) and overall survival (OS). RESULTS: One hundred seventy-nine patients were included (98 pediatric patients and 81 adult patients). Ninety pediatric patients were treated with surgery alone, whereas all adult patients received chemotherapy. The 5-year EFS and OS were 91% and 99%, respectively, for the pediatric cohort and 87% and 93%, respectively, for the adults. There were no relapses in grade 1 patients, regardless of the stage or age. Only 1 adult patient with a grade 2 IT relapsed. Among grade 3 patients, the 5-year EFS was 0.92 (0.72-0.98) for stage I/II and 0.52 (0.22-0.75) for stage III in the pediatric cohort (P = .005) and 0.91 (0.69-0.98) for stage I/II and 0.65 (0.39-0.83) for stage III/IV in the adult cohort (P = .01). Postoperative chemotherapy did not decrease relapses in the pediatric cohort. CONCLUSIONS: The grade was the most important risk factor for relapse in ovarian ITs. Among grade 3 patients, the stage was significantly associated with relapse. Adjuvant chemotherapy did not decrease relapses in the pediatric cohort; its role in adults remains unresolved. Cancer 2016;122:230-237. © 2015 American Cancer Society.

A pipeline to quantify serum and cerebrospinal fluid microRNAs for diagnosis and detection of relapse in paediatric malignant germ-cell tumours.

BACKGROUND: The current biomarkers alpha-fetoprotein and human chorionic gonadotropin have limited sensitivity and specificity for diagnosing malignant germ-cell tumours (GCTs). MicroRNAs (miRNAs) from the miR-371-373 and miR-302/367 clusters are overexpressed in all malignant GCTs, and some of these miRNAs show elevated serum levels at diagnosis. Here, we developed a robust technical pipeline to quantify these miRNAs in the serum and cerebrospinal fluid (CSF). The pipeline was used in samples from a cohort of exclusively paediatric patients with gonadal and extragonadal malignant GCTs, compared with appropriate tumour and non-tumour control groups. METHODS: We developed a method for miRNA quantification that enabled sample adequacy assessment and reliable data normalisation. We performed qRT-PCR profiling for miR-371-373 and miR-302/367 cluster miRNAs in a total of 45 serum and CSF samples, obtained from 25 paediatric patients. RESULTS: The exogenous non-human spike-in cel-miR-39-3p and the endogenous housekeeper miR-30b-5p were optimal for obtaining robust serum and CSF qRT-PCR quantification. A four-serum miRNA panel (miR-371a-3p, miR-372-3p, miR-373-3p and miR-367-3p): (i) showed high sensitivity/specificity for diagnosing paediatric extracranial malignant GCT; (ii) allowed early detection of relapse of a testicular mixed malignant GCT; and (iii) distinguished intracranial malignant GCT from intracranial non-GCT tumours at diagnosis, using CSF and serum samples. CONCLUSIONS: The pipeline we have developed is robust, scalable and transferable. It potentially promises to improve clinical management of paediatric (and adult) malignant GCTs.

Consensus on the management of intracranial germ-cell tumours.

The management of intracranial germ-cell tumours is complex because of varied clinical presentations, tumour sites, treatments and outcomes, and the need for multidisciplinary input. Participants of the 2013 Third International CNS Germ Cell Tumour Symposium (Cambridge, UK) agreed to undertake a multidisciplinary Delphi process to identify consensus in the clinical management of intracranial germ-cell tumours. 77 delegates from the symposium were selected as suitable experts in the field and were invited to participate in the Delphi survey, of which 64 (83%) responded to the invitation. Invited participants represented multiple disciplines from Asia, Australasia, Europe, and the Americas. 38 consensus statements encompassing aspects of intracranial germ-cell tumour work-up, staging, treatment, and follow-up were prepared. To achieve consensus, statements required at least 70% agreement from at least 60% of respondents. Overall, 34 (89%) of 38 statements met consensus criteria. This international Delphi approach has defined key areas of consensus that will help guide and streamline clinical management of patients with intracranial germ-cell tumours. Additionally, the Delphi approach identified areas of different understanding and clinical practice internationally in the management of these tumours, areas which should be the focus of future collaborative studies. Such efforts should translate into improved patient outcomes.

Biallelic somatic SMARCA4 mutations in small cell carcinoma of the ovary, hypercalcemic type (SCCOHT).

Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is a rare, aggressive tumor that primarily affects young women. SCCOHT has recently been identified as a monogenic disorder caused by germline and/or somatic SMARCA4 mutations. We describe a 15-year-old Caucasian female with a SCCOHT harboring a previously unreported somatic mutation in the SMARCA4 gene (c.1757delA; p.K586.fs) with loss of heterozygosity. No germline mutation was identified. Subsequent immunohistochemical staining confirmed loss of SMARCA4 protein. These molecular findings will aid with SCCOHT diagnosis through immunohistochemical staining for SMARCA4 and in the future may have implications for the management of this disease.

Familial rhabdoid tumour 'avant la lettre'--from pathology review to exome sequencing and back again.

Here we provide compelling evidence that next-generation sequencing will revolutionize diagnostics. We reappraised a case from 1991, published in 1993, describing the unique occurrence of an ovarian immature teratoma arising in a young woman and a clonally distinct intracerebral immature teratoma developing in her daughter. We conducted whole-exome sequencing on constitutional DNA from the mother and her daughter and identified a previously unreported nonsense mutation (c.3533G>A; p.Trp1178*) in the chromatin remodelling gene, SMARCA4, that was present in both individuals and was subject to nonsense-mediated decay. Tumour analysis by Sanger sequencing revealed a somatic SMARCA4 mutation in both the mother (c.2438+1G>T) and her daughter (c.3229C>T; p.Arg1077*), which are predicted to be truncating. As immature teratomas are classified as germ cell tumours, we performed a comprehensive mutation survey of 106 apparently sporadic germ cell tumours, but did not find any other clearly deleterious SMARCA4 mutations. Recently, inactivating mutations in SMARCA4 have been found in two cases of rhabdoid tumour predisposition syndrome type 2. In the light of these findings, renewed efforts to locate previously unobtainable tumour samples were successfully undertaken. Histopathological and immunohistochemical re-analysis of the daughter's tumour revealed that it was indeed a rhabdoid tumour (atypical teratoid/rhabdoid tumour). In this context, the original pathology report of the mother's ovarian tumour was re-interpreted as describing a malignant rhabdoid tumour of the ovary. This report raises the question as to whether molecular genetic analysis should be included in tumour classification, alongside more traditional microscopy-based methods. The use of new sequencing technologies, particularly when applied to archived samples, will lead to many more 'molecular rediagnoses'. This is the earliest known case of rhabdoid tumour predisposition syndrome type 2 and the first described case with an autosomal dominant pattern of inheritance, only discovered through an exome sequencing project.

EPCAM-A novel molecular target for the treatment of pediatric and adult germ cell tumors.

Germ cell tumors (GCTs) are thought to develop from totipotent primordial germ cells. Although the epithelial cell adhesion molecule (EPCAM) is expressed on embryonic stem cells as well as different tumor cells, it has not yet been extensively studied in GCTs. We analyzed EPCAM expression by quantitative RT-PCR in 48 fresh-frozen GCT specimens of different histology (10 mature teratoma, MT; 6 immature teratoma, IT; 7 dysgerminoma; 6 mixed malignant GCTs; 19 yolk sac tumor, YST) and in the GCT cell lines NCCIT, TE76.T, JAR and 2102Ep, and correlated its expression with AFP and hCG protein levels, histologic differentiation, and clinical follow-up data. EPCAM protein was visualized by immunohistochemistry of selected corresponding paraffin embedded tumor tissues. EPCAM was expressed in malignant but not in benign GCTs irrespective of age, sex, site and clinical stage of tumor (P = 0.001). In primary teratomas, EPCAM expression increased with their grade of immaturity (mean 2(-ΔCt) values: MT 0.23, IT 1.61, P = 0.007) and significantly correlated with serum AFP (P = 0.03) and hCG (P = 0.03) levels in malignant GCTs. Particularly high EPCAM levels were found in nonseminomatous GCTs such as YSTs (8.49) and choriocarcinoma (13.54). Immunohistochemical analysis verified gene expression data showing a distinct EPCAM staining in YST. Similarly in vitro, highest EPCAM expression was measured in GCT cell lines comprising yolk sac (2102Ep: 5.59) or choriocarcinoma (JAR: 10.65) components. This first comprehensive analysis of EPCAM in GCTs revealed high EPCAM expression in YSTs and choriocarcinomas. Thus, these nonseminomatous GCTs may be interesting targets for EPCAM immunotherapy, which has to be evaluated in further studies.