Germ Cell Tumors Research Articles

Nuclear medicine imaging in non-seminomatous germ cell tumors: lessons learned from the past failures

AbstractThere is an unmet need for a more accurate molecular imaging radiotracer in the field of non-seminomatous germ cell tumors (NSGCT). The clinical problem is that no single imaging modality is able to differentiate teratoma from necrotic tissue in NSGCTs, which the nuclear medicine techniques are no exception. The exponential growth in the list of potentially promising radiotracers may hold promise in the future for imaging of NSGCTs. Here, we have reviewed the past efforts and potential future advances in this field.

A Rare Case of an Aggressive Mixed Germ Cell Tumor Following Testicular Torsion

A Rare Case of an Aggressive Mixed Germ Cell Tumor Following Testicular Torsion

Advanced treatment-resistant ovarian germ cell tumor (yolk sac tumor) with successful fertility realization 20 years after combined treatment: a case report

Background. Yolk sac tumors (YST) are classified as rare malignant germ cell tumors of the ovaries, most commonly found in young patients interested in preserving fertility. YST is characterized by large size, predominantly unilateral involvement, and increased production of alpha-fetoprotein, which can be used as an important diagnostic criterion for this condition. Among all germ cell tumors, YST has the least favorable prognosis. The primary goals of YST treatment are not only to improve prognosis and quality of life but also to enable the patient to fulfill her reproductive plans in the future.Description of the clinical case. We present a clinical case of an aggressive course of yolk sac tumor in the ovary of a 15-year-old girl, requiring multiple surgeries, repeated courses of high-dose drug therapy, and bone marrow transplantation.Conclusion. This is a rare case of YST with successful preservation of reproductive function due to modern medical technologies despite aggressive treatment.

The effect of chemotherapy regimens in male germ cell tumors on the development of primary hypogonadism.

Male germ cell tumors (GCT) have excellent survival. Long-term sequelae in cancer survivors are an evolving field. We evaluated the risk of patients with GCT to develop primary hypogonadism and adherence to guideline-recommended therapy in a real-world cohort. Monocentric study at a tertiary cancer centre to evaluate treated GCT-patients (2001-2019). Post therapeutic male endocrine function, International Index of Erectile Function (IIEF)-5 and The aging males' symptoms rating scale (AMS) questionnaires were assessed. The overall response rates were low, with 44 of 402 contacted patients participating in the study. From these, 32(73%) underwent blood analysis, 42(95%) answered the IIEF-5 and 43(98%) the AMS. Latent hypogonadism (serum testosterone 8-12 nmol/l) was found in n = 9 (28%) and manifest hypogonadism (testosterone < 8 nmol/l) in n = 8 (25%). 50% (n = 21) indicated erectile dysfunction on IIEF-5 (cut off ≤ 21 pts.) and 62.8% (n = 27) reported symptomatic affection on AMS (cut off ≥ 27 pts.). Majority of tested patients revealed different degrees of hypogonadism. Standard instruments were able to detect gonadal damage in > 50%, which underscored the clinical need to evaluate endocrine function in cancer survivors. We further indicated the difficulties of today's research and provided starting points to assess barriers for study participations.

LINC00470 promotes malignant progression of testicular germ cell tumors.

Testicular germ cell tumor (TGCT) is a common malignant tumor in adolescents. Now, many long non-coding RNAs (LncRNAs) have been found to have an important function in TGCT. LINC00470 is specifically and highly expressed in TGCT, however, there is still no definite information concerning its role and underlying mechanism in TGCT. The purpose of this research was to look into the involvement of LINC00470 in TGCT and its intrinsic mechanism. UCSC and GEPIA2 databases were used to analyze the expression of LINC00470, and the BEST website was used to perform GSEA enrichment analysis, immune infiltration analysis, and drug susceptibility analysis. SiRNA transfection was used to silence LINC00470 in TCAM-2 and NCCIT cells. Clone formation and Transwell assays were performed in TGCT cells to confirm the effects of LINC00470 on clone formation, migration, and invasion. Western Blot was performed to determine the expression of proteins related to the EMT and AKT signaling pathways. LINC00470 was specifically highly expressed in TGCT, and played a role in promoting tumor cell clone formation and cell metastasis by affecting the TGF-β and PI3K-AKT-mTOR signaling pathways to regulate the epithelial-mesenchymal transition (EMT) process; LINC00470 may also play a pro-tumor role by negatively regulating immune infiltration; in addition, the expression of LINC00470 was negatively correlated with the chemosensitivity of cisplatin in TGCT patients. LINC00470 may play a significant role in the etiology and metastasis of TGCT through EMT and AKT-mediated signaling pathways.

Exploring the Incidence of Testicular Neoplasms in the Transgender Population: A Case Series.

The use of hormonal therapy and gender-affirming surgery in the transgender community has been rising during the last several years. Although it is generally safe, hormonal therapy's link to testicular cancer remains uncertain. To review the incidence of testicular cancer in specimens from gender-affirming orchiectomies at our institution and evaluate the tumors for histologic and genetic alterations. Pathology reports for gender-affirming orchiectomies (January 1, 2018, to August 1, 2023) were reviewed for testicular neoplasms, with additional analysis for chromosome 12 abnormalities. Incidence and chromosome variations were compared with those in the general population. Among 458 cases during 5.5 years, 5 germ cell neoplasms in 4 patients emerged. Our institution's annual incidence rate (159 per 100 000) is 26.5 times higher than the National Cancer Institute's previous report (6.0 per 100 000). Although they were morphologically no different from germ cell neoplasms in the general population, fluorescence in situ hybridization tests showed no i(12p) in 4 of 5 neoplasms (80%) in our cohort. The cause behind this rise in incidence remains uncertain but may be due to long term pretreatment with hormones or blockers. The lower isochromosome 12p frequency suggests an alternative mechanism driving tumor development, which requires more detailed molecular studies.

EPID-10. THE INCIDENCE OF PRIMARY BRAIN TUMORS IN JAPAN IN 2016-2019

Abstract The national cancer registries in Japan have started since 2016 and the actual number of cancer patients in including primary central nervous system (CNS) tumors in Japan was revealed. Average number of primary CNS tumors in 2016-2019 was 29,492 and the crude incidence rate per 100,000 people (CIR) was 23.30. Malignant and benign CNS tumors was 6,696 (22.7%) and 22,796 (77.3%) and each CIR was 5.29 and 18.00, respectively. Among 29,492 tumors, 10,537 (35.7%) meningioma, 5,217 (17.7%) pituitary adenoma, 4,537 (15.4%) neuroepithelial tumor, 2,730 (9.3%) neurinoma and 1,166 (4.0%) primary CNS lymphoma (PCNSL) were reported. Regarding to malignant brain tumors, 2,071 glioblastoma, 362 astrocytoma grade II, 390 anaplastic astrocytoma grade III, 138 pilocytic astrocytoma,182 oligodendroglioma grade II, 154 anaplastic oligodendroglioma grade III, 140 ependymal tumors, 128 embryonal tumors including 91 medulloblastoma, 211 germ cell tumor (GCT) were found. CIR of neuroepithelial tumor, glioblastoma, PCNSL, embryonal tumors and GCT were 3.64, 1.68, 0.93, 0.10 and 0.17, respectively. According to the Central Brain Tumor Registry of the United States (CBTRUS) (2016-2020), CIR in the US was 26.73, and age-adjusted incidence rates of primary CNS tumors per 100,000 population in the US based on the US population in 2000 (AIR) was 24.83 and AIR in Japan was 17.15. AIR of glioblastoma in the US and Japan was 3.27 and 1.05, AIR of PCNSL was 0.44 and 0.51, AIR of embryonal tumors was 0.21 and 0.16, AIR of GCTs was 0.08 and 0.27, and AIR of meningioma was 9.73 and 5.11, respectively. This report demonstrated that the incidence of neuroepithelial tumors and embryonal tumors in Japan was approximately half to one-third, whereas that of GCTs in Japan was approximately 3 times comparing to the US.

CTNI-23. DIFFERENT GUT MICROBIOTA COMPOSITION IS ASSOCIATED WITH CHEMOTHERAPY EFFICACY IN PATIENTS WITH DIFFERENT TYPES OF CENTRAL NERVOUS SYSTEM CANCER

Abstract BACKGROUND The relationship between central nervous system cancers and the gut microbiota (GM) is not well understood. The purpose of this study is to retrospective analyze the differences between the composition of the gut microbiota in patients with different neurologic tumors and their correlation with chemotherapy efficacy. METHODS A total of 44 patients participated in the study and were divided into four groups: gliocytoma (GA), medulloblastoma (MB), germ cell tumors (GT), and diffuse large B-cell lymphoma (DB) based on their pathological diagnosis. Fecal samples were collected from patients for 16S amplicon sequencing to analyze GM composition. Moreover, all the patients were classified into completed response (CR), stable disease (SD), and progressive disease (PD) groups based on the clinical outcomes of chemotherapy. PLS-DA analysis and heatmap analysis were used to reveal the correlation between GM composition and outcomes of chemotherapy. RESULTS Phyla taxa comparison showed the detailed GM composition among these four groups. The phylum of Bacteroidetes was higher in GA group when compared to the other groups. And the phylum of Fusobacteria could only be found in GA and MB groups while the phylum of Verrucomicrobia showed a significant accumulation in DB group. the genera of Ruminococcus, Gemmiger, and Parasutterella were accumulated in the patients with the completed response of chemotherapy. Besides, patients in SD group had higher abundance of the genera of Prevotella, Tyzzerella, and Odoribacter. While patients in PD group showed the higher abundance of Streptcoccus, Fusobacterium, Lachnospira, and Holemanella. CONCLUSION We firstly drew the GM composition profile of the patients with GA, MB, GT, and DB to show the different GM composition of the diseases. Moreover, the gut microbiota composition correlates with chemotherapy outcomes in central nervous system cancer patients so may serve as a potential biomarker for predicting chemotherapy efficacy.

Single-cell landscape identified SERPINB9 as a key player contributing to stemness and metastasis in non-seminomas.

Embryonal carcinoma (EC), characterized by a high degree of stemness similar to that of embryonic stem cells, is the most malignant subtype within non-seminomatous testicular germ cell tumors (TGCTs). However, the mechanisms underlying its malignancy remain unknown. In this study, we employed single-cell RNA sequencing to analyze four non-seminoma samples. Our differential expression analysis revealed high expression of SERPINB9 in metastatic EC cells. We conducted in vitro experiments to further investigate SERPINB9's role in the progression of EC. Functionally, the knockdown of SERPINB9 in NCCIT and NTERA-2 leads to a diminished migratory capability and decreased cis-platin resistance, as demonstrated by Transwell migration assay and drug sensitivity assay. Moreover, embryoid bodies showed reduced size and lower OCT4 expression, alongside heightened expression of differentiation markers AFP, ACTA2, and CD57 in shSERPINB9 cells. In vivo, the role of SERPINB9 in maintaining cancer stemness was validated by the limiting dilution assay. Mechanistically, Bulk RNA-seq further showed downregulation of ERK1/2 signaling and WNT signaling pathways with concomitant upregulation of differentiation pathways subsequent to SERPINB9 knockdown. Additionally, the analysis indicated increased levels of cytokines linked to tertiary lymphoid structures (TLS), such as IL6, IL11, IL15, CCL2, CCL5, and CXCL13 in shSERPINB9 cells, which were further validated by ELISA. Our research indicates that SERPINB9 plays a key role in driving tumor progression by enhancing tumor stemness and suppressing TLS. This study stands as the first to elucidate the molecular signature of non-seminomas at a single-cell level, presenting a wealth of promising targets with substantial potential for informing the development of future therapeutic interventions.

SURG-26. IMPROVEMENT IN PRECISION AND SURGICAL EFFICIENCY USING THE STEALTH AUTOGUIDE™

Abstract INTRODUCTION The Stealth Autoguide™ (Medtronic) automatically determines the path for guiding instruments based on the created surgical plan. It seamlessly integrates continuous real-time navigation with robotic alignment capabilities, enhancing intraoperative workflow efficiency and supporting precise positioning. Our institution has achieved favorable results with surgeries utilizing the Stealth Autoguide™, and we report these outcomes and our future prospects. METHODS We conducted 15 surgeries at our institution using the StealthStation S8 (Medtronic) linked with the Stealth Autoguide™. The average age was 56.2 years, with 10 males and 5 females, all under general anesthesia. RESULTS The cases included 11 gliomas, 2 primary central nervous system lymphomas, 1 germ cell tumor, and 1 brain abscess. Applications of the Stealth Autoguide™ included 7 biopsies (6 burr holes, 1 craniotomy), 6 placements of fenestrations, and 2 tubing placements. The biopsies allowed for quick and reliable tissue sampling. In fenestration cases, it was possible to position quickly and precisely at the target, placing it at the planned site with high accuracy. Additionally, by using a 3D endoscopic system, surgeons could view both the surgical field and navigation screens simultaneously without shifting their gaze, enhancing safety during procedures. In the case of an intraventricular germ cell tumor, tubing preceded by ViewSite™ allowed for a safe and clear surgical field. CONCLUSION Surgeries using the Stealth Autoguide™ were conducted safely and efficiently, regardless of the surgical technique, achieving high-precision positioning. Continuing to utilize this system is expected to improve the accuracy, safety, and reproducibility of surgeries, thereby reducing the burden on patients.

RTID-05. STUDY PROTOCOL: A MULTICENTER, INTERNATIONAL RANDOMIZED CONFIRMATORY TRIAL: LOW-ENERGY X-RAY INTRAOPERATIVE RADIATION THERAPY (LEX-IORT) VS. ADJUVANT FRACTIONATED STEREOTACTIC RADIOTHERAPY (FSRT) IN THE MANAGEMENT OF BRAIN METASTASES (LEXIMATE)

Abstract BACKGROUND Fractionated stereotactic radiotherapy to the resection cavity boosts local control of resected brain metastases significantly. However, start of systemic tumor-directed treatment may be protracted and in-hospital times prolonged. Lately, lex-ioRT of BM has been described as a safe and effective one stop-shop treatment modality with a 1-year local control rate of up to 98% while potentially improving patient convenience. Study Design: The LEXIMATE-trial is a multicenter, international, randomized open-label confirmatory trial comparing lex-IORT with FSRT of resected BM. In the experimental arm, INTRABEAM (Carl Zeiss Meditec AG) is used to deliver IORT by application of 50-kV photons at a standard dose of 30 Gy prescribed to the applicator surface. Standard linear accelerator or Gamma Knife based FSRT (3-7 fractions) to the surgical bed is used in the control arm. The primary endpoint is the cumulative incidence of local recurrences (as per RANO-BM) considering death without prior local recurrence as competing event. Inclusion criteria include histologically confirmed BM with indication for resection according to EANO-ESMO/ASCO-SNO-ASTRO guidelines, ≤5 other brain lesions compatible with BM and amenable to radiosurgery and history of solid cancer or CT scan suggestive for localized or metastasized solid cancer (except germ cell tumors, lymphoma, small-cell lung cancer). The resection cavity must be &amp;lt;5cm in size, IORT doses to brainstem or optical tract may not exceed 8 Gy. Study design: Randomized, open-label, non-inferiority. Sample size: 70 patients per group to show a non-inferiority of the experimental therapy compared to the control therapy with a power of approximately 80%. DISCUSSION The best radio-oncologic procedure for resected BM remains under debate. The LEXIMATE-trial offers an opportunity to provide more solid prospective data on effectiveness, safety and patient comfort both for established and new RT techniques.

NCOG-43. THE APPLICATION OF INDUCTION CHEMOTHERAPY COMBINED WITH RADIOTHERAPY IN YOUNG ADULTS WITH CNS GERM CELL TUMORS

Abstract BACKGROUND Central nervous system (CNS) germ cell tumors are rare brain neoplasms, accounting for approximately 0.3-0.5% of all CNS tumors. A combination of radiotherapy and chemotherapy is the standard of care (SOC) in pediatric patients. However, there is no SOC for young adult or adult patients. This study evaluates a regimen of induction chemotherapy followed by radiation in treating young adults with CNS germ cell tumors. METHOD Nine young adult patients diagnosed with pure CNS germinomas were identified in our institution. They underwent a treatment regimen of induction chemotherapies that were planned for four cycles and consisted of bleomycin (three doses per cycle), cisplatin (five doses per cycle) and etoposide (five doses per cycle) followed with whole brain and/or ventricular radiotherapy. The patients’ overall survival (OS), neurological function (including cognition), and adverse events (AE) were analyzed. RESULT Among the nine patients (seven males and two females), the median age is 20 years (range: 17-33 years). They received bleomycin, cisplatin and etoposide (median: two cycles, range: 1-4), and subsequent radiotherapy with plans based on tumor location by radiation oncologists, with a median radiotherapy dose of 45 Gy (range: 36-50.4). Seven patients had a complete response after chemotherapy. The median OS is 53 months (range: 39-121). There is no identifiable cognitive impairment by neurological exam. All patients experienced at least one, reversible, grade 3 AE of myelosuppression. All patients return to their normal baseline including employment. Results of neuropsychological evaluation and all AEs will be presented at the conference. CONCLUSION Induction chemotherapy followed by radiotherapy is potentially safe and effective with manageable and reversible side effects from chemotherapy without cognitive and functional impairment in the nine young adult patients with CNS germ cell tumors. A prospective study of this approach in a clinical trial setting is warranted.

NCMP-04. IMPLANTATION METASTASIS FOLLOWING BIOPSY OF THALAMIC GERMINOMA – A CASE REPORT AND REVIEW OF LITERATURE

Abstract Germ cell tumors commonly develop in the pineal and suprasellar regions, with the most common germ cell tumor being germinomas. In this report, a 22-year-old male presented with progressive right-sided weakness and his imaging was consistent a thalamic high grade glioma. A stereotactic biopsy was performed, revealing a germinoma, but radiation therapy was not done and patient was lost to follow up. He was readmitted due to ulcerative tumor growth at the previous skin incision, and imaging revealed tumor progression with implantation metastasis along the tract of the previous biopsy. The scalp tumor was excised and histopathologic studies confirmed that it was proliferation of the previous germinoma. He was discharged well but was unfortunately unable to follow up at the clinic. Thalamic germinomas are difficult to diagnose and treat because of their rarity. Here we underscore the importance of careful patient selection, precise biopsy techniques, thorough postoperative management and close radiographic surveillance to minimize the risk of implantation metastasis and promptly treat it if it occurs.

EPID-36. CLINICAL FEATURES OF 614 PRIMARY INTRACRANIAL GERM CELL TUMORS: AN 15-YEAR EXPERIENCE OF A SINGLE CENTER IN CHINA

Abstract Incidence of primary intracranial germ cell tumors (ICGCT) in Asian countries is higher than Western countries. This study aims to describe the characteristics of ICGCT patients in China. Data on all patients with ICGCT who were seen at the Department of Neuro-oncology, Sanbo Brain Hospital, Capital Medical University from 2007 to 2022 were collected retrospectively. Patient demographics, disease characteristics and treatment outcomes were analyzed. A total of 614 patients were identified, with 309 germinomas and 305 non-germinomatous germ cell tumors (NGGCT). The median age at diagnosis was 12.8 years. The male-female ratio is 2.4 to 1. The primary disease sites were mainly pineal gland and suprasellar region. Adults (age≥23) were more likely to develop germinomas (65.3%). 78% patients received radiotherapy after initial diagnosis. In M0 patients, whole brain radiotherapy was the most common approach, while in M+ was craniospinal radiotherapy. Whole ventricle radiotherapy was uncommon (4%). The most common chemotherapy regimen for germinoma was a combination of bleomycin, cisplatin and etoposide/tenipside; while for the NGGCT was ifosfamide combined with carboplatin/cisplatin and etoposide. For germinoma, the median recurrence-free survival (RFS) and overall survival (OS) were 150.3 months and 222 months; the 10 year RFS and OS were 58.2% and 85.1%, respectively. For NGGCT, the median RFS and OS were 80.4 months and 166.7 months; the 10 year RFS and OS were 46.9% and 60.5%. At relapse, four (0.65%) developed secondary malignancies. Seven (1.14%) developed extracranial dissemination. Chemotherapy and radiotherapy could improve the RFS and OS. Higher radiation dose was associated with better prognosis. The prognosis of focal radiotherapy alone was poor. M0 germinoma treated with focal radiotherapy alone were more likely relapse. This study suggested that treatment outcomes of our ICGCT patients are comparable with those in Western centers. Adjuvant chemotherapy and whole brain/craniospinal radiotherapy are pivotal treatment.

PATH-24. NOVEL MOLECULAR SUBTYPES IDENTIFIED IN INTRACRANIAL GERM CELL TUMORS SHOWED UNIQUE WHOLE-GENOME METHYLATION PROFILE

Abstract BACKGROUND By integrating whole-genome sequencing (WGS) and RNA-seq data, we found that intracranial germ cell tumors (IGCTs) can be divided into three distinct molecular subtypes: immune-hot, MYC/E2F, and SHH, each characterized by a unique profile of genomic abnormalities. To further define these subtypes, we subsequently performed whole-genome bisulfate sequencing (WGBS) on IGCT tumors METHODS Within our prior discovery cohort (n=110), DNA from 84 samples was available for profiling methylation levels using Whole Genome Bisulfite Sequencing (WGBS). Fastq data was aligned to the human reference genome (hg19), with duplicates removed, and DNA methylation was extracted using bismark pipeline (ver0.24.0). After quality control, weight methylation level was calculated for each CpG island as the sum of methylated reads divided by coverage. To identify IGCTs molecular groups, we applied hierarchical consensus k-means clustering to the most variant methylated CpG island (n=1000) across 84 IGCTs tumor tissues. The methylation level of RNA-seq subtypes was visualized to further clarify the molecular subtypes of IGCTs RESULTS Unsupervised clustering revealed that IGCTs can be divided into three groups based on the CpG island methylation levels: hypomethylation group (n=32), moderate methylation group (n=27), and hyper methylation group (n=25). The hypomethylation and moderate methylation group are predominantly observed in germinoma (&amp;gt;90%). In contrast, hypermethylation group comprises the majority of non-germinomatous germ cell tumors. Furthermore, these subgroups derived from methylation analysis are highly consistent with the molecular subtypes previously defined through gene transcription profile analysis. We observed that the majority of MYC/E2F subtype (24/33) belonged to the hypomethylation group, whereas the majority of immune-hot subtype (14/23) fell into the moderate methylation group. The SHH subtype was the most common within the hypermethylation group (18/26) CONCLUSIONS The three molecular IGCT subtypes showed unique methylation profile. These results indicate different mechanisms of tumorigenesis among the subtypes and pave the way for the clinical application of methylation-based subtyping.

QOL-07. LONG-TERM FOLLOW-UP OF PHYSICAL FUNCTION AND SOCIAL CONDITIONS IN CENTRAL NERVOUS SYSTEM GERM CELL TUMORS

Abstract BACKGROUND This paper presents an analysis of iving and social conditions from a long-term follow-up of Phase II clinical trial for central nervous system germ cell tumors conducted between 1995 and 2003. METHODS A retrospective analysis was performed on 228 cases, including 161 germinomas, 66 non-germinomas, and 1 mature teratoma, over a median follow-up of 222 months. There were 56 recurrences and 39 deaths recorded. The analysis at the final follow-up included final educational level, employment status, activities of daily living (ADLs), marital and parental status, and hormone replacement therapy. The study targeted 157 cases with more than 10 years of follow-up data. RESULTS At 20 years post-treatment, survival rates were 91% for germinomas and 65% for non-germinomas. At the last follow-up, ages ranged from 19 to 58 years (median 36 years). The Karnofsky Performance Status (KPS) was 80 or higher in 118 cases, 70 in 7 cases, and 60 or lower in 32 cases. Educational achievements were: elementary school in 1 case, middle school in 8, high school in 52, university in 45, and graduate school in 2. Employment status showed 37 unemployed, 4 in school, 23 part-time, 80 full-time, and 2 homemakers. Childbirth was reported in 16 men (18%) and 4 women (16%). The frequency of a KPS≧80 at the final follow-up was higher in initial germinoma cases than in non-germinoma cases (80 vs 62%, p=0.04), and was also higher in cases without recurrence (83 vs 47%, p&amp;lt;0.0001). Only the proportion of growth hormone supplementation showed a significant correlation with KPS (≧80: 19% vs &amp;lt;80: 3%, p=0.03). CONCLUSION Long-term social outcomes are favorable for germinoma patients without recurrence, while non-germinoma patients who have recurred and survived face tougher conditions, indicating significant treatment impacts. Managing treatment intensity and ensuring comprehensive long-term follow-up are crucial.

TMIC-13. INTEGRATING SNRNASEQ AND SPATIAL TRANSCRIPTOME (ST) SHOWS DIVERSE TRANSCRIPTOMIC LANDSCAPE FOR TUMOR MICROENVIRONMENT (TME) IN INTRACRANIAL GERMINOMAS

Abstract The incidence of intracranial germ cell tumors is 5-8 times higher in East Asia and histologically, germinoma is well known to show intense lymphocytic infiltrates. In spite of germinoma’s well known immune infiltration, there have only been a few studies on its tumor micro-environment (TME). There has been no study using the recent and comprehensive techniques of single nucleus sequencing or spatial transcriptomics to study its TME. In this study, we studied snRNAseq (Chromium 10X) of FFPE tissues of 24 intracranial germinomas, and spatial transcriptomes (STs) (Visium Spatial) from fresh tissues from ten matched cases. For the TME, in contrast to common belief, macrophages and fibroblasts were equally represented as T- and NK-cells as immune cells. Clinical stage correlated with a lesser proportion of fibroblasts and T- and NK-cells. There was no correlation with proportion of tumor cells with either focal vs bifocal disease or clinical stage. Common gene modules (non-negative matrix factorization) were epithelial-mesenchymal transition (complete and partial), cell cycle and immune cells. Cell interaction analysis showed strong interaction between germ cells and macrophages involving CXCL, MIF and MK pathways. By ligand-receptor analysis, MIF combined with CD74 might promote tumor development. For ten cases, we studied STs with fresh tissues and integrated the results with snRNSeq, deconvoluting the spots for ST using snRNAseq cell types as reference (SPOTight) and achieved integrated single cell expression atlases of the STs (Seurat package). STs revealed a similar CNV plot pattern as those derived from snRNAseqs. Multimodal Intersection Analysis integrated significant genes based on snRNAseq and different regions’ significant genes based on STs. There was correlation between the expression of the four gene modules for tumor and immune cells for cell neighborhood. In conclusion, we showed in details the heterogenous expression landscape of TME of germinomas.

Replenishing co-downregulated miR-100-5p and miR-125b-5p in malignant germ cell tumors causes growthinhibition through cell cycle disruption.

MicroRNAs (miRNAs) are short, nonprotein-coding RNAs, and their expression is dysregulated in malignant germ cell tumors (GCTs). Here, we investigated the causes and consequences of downregulated miR-99a-5p/miR-100-5p (functionally identical) and miR-125b-5p levels in malignant GCTs regardless of age, site, or subtype. Quantitative RT-PCR was used to assess miR-99a-5p/miR-100-5p, miR-125b-5p, and associated gene expression in malignant GCT tissues/cell lines [seminoma (Sem), yolk sac tumor (YST), embryonal carcinoma (EC)]. Cells were treated with demethylating 5-azacytidine and pyrosequencing was performed. Combination miR-100-5p/miR-125b-5p mimic replenishment was used to treat malignant GCTcells. Global messenger RNA (mRNA) targets of the replenished miRNAs were identified and Metascape used to study pathway effects. We found that expression levels of miR-99a-5p/miR-100-5p and miR-125b-5p, their respective pri-miRNAs, and associated genes from chromosomes 11 and 21 (chr11/chr21) were downregulated and highly correlated in malignant GCTcells. Treatment with 5-azacytidine caused upregulation of these miRNAs, with pyrosequencing revealing hypermethylation of their chr11/chr21 loci, likely contributing to miR-100-5p/miR-125b-5p downregulation. Combination miR-100-5p/miR-125b-5p mimic replenishment resulted in growth inhibition in Sem/YST cells, with miR-100-5p/miR-125b-5p mRNA targets enriched in downregulated genes, which were involved in cell cycle (confirmed by flow cytometry) and signaling pathways. Knockdown of the miR-100-5p/miR-125b-5p target tripartite motif containing 71 (TRIM71kd) recapitulated miR-100-5p/miR-125b-5p replenishment, with growth inhibition and cell cycle disruption of Sem/YST/EC cells. Further, replenishment led to reduced lin-28 homolog A (LIN28A) levels and concomitant increases in let-7 (MIRLET7B) tumor suppressor miRNAs, creating a sustained reversion of cell phenotype. In summary, combination miR-100-5p/miR-125b-5p mimic replenishment or TRIM71kd caused growth inhibition in malignant GCTcells via cell cycle disruption. Further studies are now warranted, including mimic treatment alongside conventional platinum-based chemotherapy.

Factors impacting tumor displacement artifact and pseudo-lymphovascular invasion in testicular germ cell tumors.

Testicular germ cell tumors are susceptible to tumor displacement artifact (TDA), which produces pseudo-lymphovascular invasion (LVI) and confounds the identification of true LVI. Our study aimed to evaluate tumor displacement artifact and pseudo-LVI in testicular germ cell tumors and determine if prolonged fixation improves histological quality. A retrospective search identified 121 orchiectomies with slides that were reviewed to assess TDA and pseudo-LVI. Seminoma had more TDA (68% vs 45%, P= .01) and pseudo-LVI (53% vs 19%, P< .001) than mixed germ cell tumor. Seminoma and mixed germ cell tumor with TDA and pseudo-LVI were larger than those without. Mixed germ cell tumor with ≥50% composition of seminoma had a higher rate of TDA (89% vs 38%, P= .008) and pseudo-LVI (44% vs 15%, P= .06) than those with less. TDA was reduced in seminoma with >1 night fixation compared to no fixation (50% vs 82%, P= .046), with a similar trend in mixed germ cell tumor (31% vs 60%, P= .15). A trend in reduction of pseudo-LVI was seen with >1 night fixation compared to no fixation in seminoma (64% vs 39%, P= .12). Seminomas and larger germ cell tumors were more prone to TDA and pseudo-LVI. Prolonged formalin fixation improved histological quality intesticular germ cell tumors. Based on these data, we recommend fixation for at least 2 nights before sectioning orchiectomy specimens, particularly for larger tumors.

Current Trends in the Surgical Management of Yolk Sac Tumors

Mediastinal yolk sac tumors (YST) constitute a highly malignant subtype of primary non-seminomatous germ cell tumors, which are often locally advanced and unresectable at diagnosis. Due to their rarity and aggressiveness, there is not yet a standard optimal treatment approach. A widely employed multimodal strategy involves neoadjuvant cisplatin-based combination chemotherapy followed by consolidation surgery. Tumor infiltration into the lungs and adjacent cardiovascular structures is common, such that surgical intervention typically requires extensive resections, performed either by sternotomy or thoracotomy. For this review, we extensively searched the PubMed and Embase medical databases, identifying articles describing surgical treatment of mediastinal yolk sac tumors. The current literature provides limited details regarding the utilized surgical procedures, leaving clinicians without comprehensive guidance about the demanding nature of these resections. Here, we present a narrative description of the range of current surgical procedures. By highlighting these techniques, we provide a comprehensive overview of the current surgical landscape, thereby helping clinicians understand the potential complexities and considerations involved in managing these rare and aggressive tumors.