Current outstanding challenges in germ cell tumors.

PURPOSE OF REVIEW: Despite the remarkable advances in the treatment of germ cell tumors (GCT), several challenges remain. This review aims to highlight some of these challenges and provide guidance on how to navigate through them. RECENT FINDINGS: Patients with International Germ Cell Cancer Collaborative Group poor risk disease have worse prognosis and investigating novel therapeutic interventions are warranted in this population. Patients with brain metastases require a multidisciplinary approach by a group of clinicians experienced in the management of germ cell tumors. Patients with platinum refractory disease have poor prognosis and development of novel treatment options is urgently needed. Conventional tumor markers including alpha fetoprotein and human chorionic gonadotropin remain standard. Development of novel biomarkers to detect minimal residual disease or teratoma is needed. SUMMARY: Management of patients with GCT requires a multidisciplinary approach. Patients should preferably be evaluated at tertiary care centers with expertise in the management of this disease.

Impact of teratoma on survival probabilities of patients with metastatic non-seminomatous germ cell cancer: Results from the IGCCCG Update Consortium.

AIMS: To resolve the ongoing controversy surrounding the impact of teratoma (TER) in the primary among patients with metastatic testicular non-seminomatous germ-cell tumours (NSGCT). PATIENTS AND METHODS: Using the International Germ Cell Cancer Collaborative Group (IGCCCG) Update Consortium database, we compared the survival probabilities of patients with metastatic testicular GCT with TER (TER) or without TER (NTER) in their primaries corrected for known prognostic factors. Progression-free survival (5y-PFS) and overall survival at 5 years (5y-OS) were estimated by the Kaplan-Meier method. RESULTS: Among 6792 patients with metastatic testicular NSGCT, 3224 (47%) had TER in their primary, and 3568 (53%) did not. In the IGCCCG good prognosis group, the 5y-PFS was 87.8% in TER versus 92.0% in NTER patients (p = 0.0001), the respective 5y-OS were 94.5% versus 96.5% (p = 0.0032). The corresponding figures in the intermediate prognosis group were 5y-PFS 76.9% versus 81.6% (p = 0.0432) in TER and NTER and 5y-OS 90.4% versus 90.9% (p = 0.8514), respectively. In the poor prognosis group, there was no difference, neither in 5y-PFS [54.3% in TER patients versus 55.4% (p = 0.7472) in NTER], nor in 5y-OS [69.4% versus 67.7% (p = 0.3841)]. NSGCT patients with TER had more residual masses (65.3% versus 51.7%, p < 0.0001), and therefore received post-chemotherapy surgery more frequently than NTER patients (46.8% versus 32.0%, p < 0.0001). CONCLUSION: Teratoma in the primary tumour of patients with metastatic NSGCT negatively impacts on survival in the good and intermediate, but not in the poor IGCCCG prognostic groups.

Evaluation and Management of Testicular Cancer After Late Relapse.

A 41-year-old man presented to his primary care physician with a 1-month history of left neck adenopathy in the context of a history of nonseminomatous germ cell tumors (NSGCTs). In 2011, the patient was treated for stage IB (T2N0M0S0) right-sided NSGCTs of the testis, which were 95% embryonal and 5% yolk sac tumors. He underwent a right radical orchiectomy and was followed until 2022 without recurrence. In the work-up for his adenopathy, laboratory results for human chorionic gonadotropin, lactate dehydrogenase, and α-fetoprotein were normal. CT scans confirmed clustered enlarged lymph nodes in the left lower spinal accessory posterior triangle, enlarged left lower neck lymph nodes, and several foci of enlarged left retroperitoneal periaortic lymph nodes. Fine needle aspiration of a left neck lymph node identified malignant tumor cells. A left neck dissection showed embryonal carcinoma in 12 of 28 nodes. Immunostaining showed the tumor cells were positive for SALL4 and CD30 but negative for CD117. This patient likely had a contralateral late relapse of his original right NSGCT after 11 years of remission. The patient's original cancer was on the right side, with recurrence surrounding the aorta on the contralateral side, representing an atypical pattern of spread.

New insights on testicular cancer prevalence with novel diagnostic biomarkers and therapeutic approaches.

BACKGROUND: Testicular cancer (TC), comprising merely 1% of male neoplasms, holds the distinction of being the most commonly encountered neoplasm among young males. RECENT FINDINGS: Most cases of testicular neoplasms can be classified into two main groups, namely germ cell tumors representing approximately 95% of the cases, and sex cord-stromal tumors accounting for about 5% of the cases. Moreover, its prevalence is on the rise across the globe. TC is a neoplastic condition characterized by a favorable prognosis. The advent of cisplatin-based chemotherapeutic agents in the latter part of the 1970s has led to a significant enhancement in the 5-year survival rate, which presently surpasses 95%. Given that TC is commonly detected before reaching the age of 40, it can be anticipated that these individuals will enjoy an additional 40-50 years of life following successful treatment. The potential causes of TC are multifactorial and related to different pathologies. Accurate identification is imperative to guarantee the utmost efficacious and suitable therapy. To a certain degree, this can be accomplished through the utilization of blood examinations for neoplastic indicators; nonetheless, an unequivocal diagnosis necessitates an evaluation of the histological composition of a specimen via a pathologist. CONCLUSION: TC is multifactorial and has various pathologies, therefore this review aimed to revise the prenatal and postnatal causes as well as novel diagnostic biomarkers and the therapeutic strategies of TC.

MicroRNAs in Testicular Germ Cell Tumors: The Teratoma Challenge.

Testicular germ cell tumors (TGCTs) are relatively common in young men, making accurate diagnosis and prognosis assessment essential. MicroRNAs (miRNAs), including microRNA-371a-3p (miR-371a-3p), have shown promise as biomarkers for TGCTs. This review discusses the recent advancements in the use of miRNA biomarkers in TGCTs, with a focus on the challenges surrounding the noninvasive detection of teratomas. Circulating miR-371a-3p, which is expressed in undifferentiated TGCTs but not in teratomas, is a promising biomarker for TGCTs. Its detection in serum, plasma, and, potentially, cystic fluid could be useful for TGCT diagnosis, surveillance, and monitoring of therapeutic response. Other miRNAs, such as miR-375-3p and miR-375-5p, have been investigated to differentiate between TGCT subtypes (teratoma, necrosis/fibrosis, and viable tumors), which can aid in treatment decisions. However, a reliable marker for teratoma has yet to be identified. The clinical applications of miRNA biomarkers could spare patients from unnecessary surgeries and allow for more personalized therapeutic approaches. Particularly in patients with residual masses larger than 1 cm following chemotherapy, it is critical to differentiate between viable tumors, teratomas, and necrosis/fibrosis. Teratomas, which mimic somatic tissues, present a challenge in differentiation and require a comprehensive diagnostic approach. The combination of miR-371 and miR-375 shows potential in enhancing diagnostic precision, aiding in distinguishing between teratomas, viable tumors, and necrosis. The implementation of miRNA biomarkers in TGCT care could improve patient outcomes, reduce overtreatment, and facilitate personalized therapeutic strategies. However, a reliable marker for teratoma is still lacking. Future research should focus on the clinical validation and standardization of these biomarkers to fully realize their potential.

Testicular cancer with small metastatic burden: optimal approach in 2024.

PURPOSE OF REVIEW: Recent advancements in the management of clinical stage II (CS II) testicular cancer have transformed it into a predominantly curable condition. This success in treatment advancements has markedly extended patient survival. However, these treatments carry risks and morbidities, which is important to consider given the disease's impact on young men and the emerging understanding of long-term treatment consequences. RECENT FINDINGS: Emerging data support primary retroperitoneal lymph node dissection (RPLND) for select CS II seminoma patients, with similar short-term outcomes to chemotherapy but less treatment intensity. Recent studies have also challenged the reflexive use of adjuvant chemotherapy for pathologic node-positive disease, as growing evidence shows low relapse rates regardless of nodal stage. Furthermore, novel biomarkers like circulating serum microRNA-371a-3p levels can help predict the presence of viable germ cell tumor at time of RPLND. SUMMARY: Advances in risk stratification and therapy enable personalized de-escalation approaches for oligometastatic testicular cancer, optimizing survivorship. Upfront RPLND, reassessing adjuvant systemic therapy for RPLND pN+ disease, and novel biomarkers will shape precision treatment to achieve high cure rates with excellent quality of life. Ongoing trials of reduced-intensity regimens, accurate prognostic models, improved surgical strategy, and emerging biomarkers represent the next frontier in tailored curative therapy.

The prognostic impact of treatment centralization in patients with testicular germ cell tumors: analysis of hospital-based cancer registry data in Japan.

BACKGROUND: To identify the prognostic impact of treatment centralization in patients with testicular germ cell tumors (TGCT). METHODS: We used a hospital-based cancer registry data in Japan to extract seminoma and non-seminoma cases that were diagnosed in 2013, histologically confirmed, and received the first course of treatment. To compare the 5-years overall survival (OS) rates of patients stratified by institutional care volume, we performed a Cox proportional hazards regression analysis using inverse probability of treatment weighting (IPTW) method to adjust patient backgrounds. RESULTS: A total of 1767 TGCT patients were identified. The 5-years OS rates for stage II and III TGCT patients treated at low-volume institutions (< 7 cases) were significantly worse than high-volume institutions (≥ 7 cases) (91.2% vs. 83.4%, p = 0.012). Histological stratification revealed that 5-year OS rates for stage II and III seminoma patients in the low-volume group were significantly worse than the high-volume group (93.5% vs. 84.5%, p = 0.041). Multivariate OS analysis using an IPTW-matched cohort showed that institutional care volume was an independent prognostic factor (hazard ratio 2.13 [95% confidence interval: 1.23-3.71], p = 0.0072). CONCLUSION: Our results indicate that stage II and III TGCT patients experience lower survival rates at low-volume institutions and would benefit from treatment centralization.

Treatment outcomes and risk factors of patients with intracranial germ cell tumour with choriocarcinoma element or ß-HCG level higher than 500 IU/L.

BACKGROUND: In previous studies, patients with intracranial germ cell tumour (iGCT) with pure choriocarcinoma or mixed germ cell tumours with choriocarcinoma element showed similar dismal prognoses, with median overall survival (OS) of 22 months and 1-year survival rate of approximately 60%. However, these conclusions need to be updated because radiotherapy, which is the mainstay for this disease, was not applied in a number of patients. Additionally, prognostic factors need to be explored in this population. METHODS: Clinical data of patients with iGCTs with histologically confirmed choriocarcinoma element or beta-human chorionic gonadotropin (ß-HCG) > 500 IU/L were collected from the archives of our institution and retrospectively studied. RESULTS: A total of 76 patients were eligible for this study. Except for two early deaths, all patients received radiotherapy (craniospinal irradiation [CSI], n = 23; non-CSI, n = 51). The median follow-up duration for the entire series was 63 months (range, 6-188 months). The 5-year event-free survival (EFS) and OS rates were 81.5% and 84.1%, respectively. Among patients who did not have early death or progressive disease after induction chemotherapy, multivariate analysis revealed that chemotherapy cycles (> 4 vs. ≤ 4) (hazard ratio [HR] for EFS 0.144, p = 0.020; HR for OS 0.111, p = 0.028) and ß-HCG levels (> 3000 IU/L vs. ≤ 3000 IU/L) (HR for EFS 4.342, p = 0.059; HR for OS 6.614, p = 0.033) were independent factors for survival. CONCLUSIONS: Patients with iGCTs with choriocarcinoma element or ß-HCG > 500 IU/L showed improved survival with radiotherapy-based treatments. Additional chemotherapy cycles could result in additional survival benefits. Patients with ß-HCG level > 3000 IU/L had poorer prognosis.

Epidemiology, Management, and Survival Outcomes of Germ Cell Cancer in Southern Portugal: A Population-Based Study (2008-2012).

INTRODUCTION: Building on previous suboptimal survival results, we aimed to perform a study of the epidemiological status, management, and outcomes of germ cell tumors (GCT) in the Portuguese population. MATERIALS AND METHODS: Retrospective populational study of GCT cases diagnosed between 2008 and 2012 in southern Portugal. Joinpoint regression was used to compute average annual percentage change (AAPC) in incidence rate. ESMO/EAU guidelines served as references to evaluate compliance. Association between compliance with guidelines and hospital GCT case load was performed by generalized estimating equation. Survival was calculated by Kaplan-Meier and prognostic factors by Cox models. RESULTS: The study included 401 GCT male cases. The AAPC was 5.4% (IC 95% 3.3-7.4, P < .001) from 1999 (an earlier cohort published) to 2012. The median time to diagnosis was 63 days (Q25 = 33 days; Q75 = 114 days; IQR = 81 days). For stage II/III the median time to start chemotherapy was 34 days (Q25 = 22 days; Q75 = 56 days; IQR = 22 days). In 86% cases there was noncompliance with guidelines for the orchiectomy report, 6% for staging, 38% for tumor markers evaluation, 20% for treatment and 25% for chemotherapy dose intensity. The 5-year overall survival was 93.8% (95% CI, 91.3%-96.4%). Hospitals that managed ≤ 3 GCT cases/ year had higher odds for noncompliance with guidelines of blood markers, treatment and dose intensity. None of GCT healthcare access and management factors studied were associated with prognosis. CONCLUSIONS: The burden of GCT is rising in Portugal. Although survival has improved, efforts must be made to nationally enhance training and expertise in GCT and support region adapted models of centralization of care.

Second Hematologic Malignancies Associated With Primary Mediastinal Germ Cell Tumors: A Population-based Study.

BACKGROUND: Studies addressing second hematologic malignancies (SHMs) in patients with primary mediastinal germ cell tumors (PMGCTs) are scarce. To better describe this phenomenon, we analyzed a large case series from a population-based registry. METHODS: The Surveillance, Epidemiology, and End Results database was used to report the clinical characteristics and incidence of SHMs in patients with PMGCT. RESULTS: Among 1297 PMGCTs, 27 cases (2.08%) of SHM were found, with a median latency period of 12 months (95% CI: 5-41). All SHM occurred in males, 20 of whom (74.1%) had a previous nonseminomatous tumor. Acute myeloid leukemia was the most frequent SHM, accounting for 13 cases, 4 of which were acute megakaryoblastic leukemia that occurred within 5 months of diagnosis. The median survival after the diagnosis of SHM was 6 months (95% CI: 2-41). The risk of SHM was significantly higher than expected for the reference population, with a standardized incidence ratio of 6.21 (95% CI: 3.31-10.62) and an absolute excess risk of 19.19 per 10,000 person-years. CONCLUSIONS: Patients with PMGCT are at a higher risk of developing SHMs than the general population, particularly acute myeloid leukemia. This risk ranges from synchronous diagnosis of acute megakaryoblastic leukemia to the later onset of other hematological disorders that might be related to PMGCT therapies. Our findings may help create follow-up schedules for patients with PMGCT and raise the level of suspicion surrounding this association.

Adolescent and Young Adult Germ Cell Tumors: Epidemiology, Genomics, Treatment, and Survivorship.

Innovations in the care of adolescent and young adult (AYA) germ cell tumors (GCTs) are needed for one of the most common AYA cancers for which treatment has not significantly changed for several decades. Testicular GCTs (TGCTs) are the most common cancers in 15- to 39-year-old men, and ovarian GCTs (OvGCTs) are the leading gynecologic malignancies in women younger than 25 years. Excellent outcomes, even in widely metastatic disease using cisplatin-based chemotherapy, can be achieved since Einhorn and Donohue's landmark 1977 study in TGCT. However, as the severity of accompanying late effects (ototoxicity, neurotoxicity, cardiovascular disease, second malignant neoplasms, nephrotoxicity, and others) has emerged, efforts to deintensity treatment and find alternatives to cisplatin have taken on new urgency. Current innovations include the collaborative design of clinical trials that accrue GCTs across all ages and both sexes, including adolescents (previously on pediatric trials), and OvGCT (previously on gynecologic-only trials). Joint trials accrue larger sample sizes at a faster rate and therefore evaluate new approaches more rapidly. These joint trials also allow for biospecimen collection to further probe GCT etiology and underlying mechanisms of tumor growth, thus providing new therapeutic options. This AYA approach has been fostered by The Malignant Germ Cell International Consortium, which includes over 115 GCT disease experts from pediatric, gynecologic, and genitourinary oncologies in 16 countries. Trials in development incorporate, to our knowledge, for the first time, molecular risk stratification and precision oncology approaches on the basis of specific GCT biology. This collaborative AYA approach pioneering successfully in GCT could serve as a model for impactful research for other AYA cancer types.

A novel lactate dehydrogenase-based risk score model to predict the prognosis of primary central nervous system germ cell tumor treated with chemoradiotherapy.

BACKGROUND: The prognostic role of lactate dehydrogenase (LDH) has been confirmed in many malignant tumors, but the role of serum LDH in primary central nervous system germ cell tumor (GCT) remains unknown. This study aimed to assess the prognostic value of LDH in GCT patients and develop a nomogram to predict prognosis in patients undergoing chemoradiotherapy. METHODS: A total of 161 patients with GCT were included in this study. Using a restricted cubic spline (RCS) model, the optimal cutoff point for LDH was determined to be 217 U/L. The survival of GCT patients was evaluated using the Kaplan-Meier method and log-rank test to analyze the effects of LDH levels. Univariate Cox regression, multivariate Cox regression, and LASSO Cox regression were conducted to identify prognostic factors, which were incorporated into a nomogram for predicting overall survival (OS). The predictive accuracy of the nomogram was assessed using the C-index, calibration curve, area under the time-dependent receiver operating characteristic curve (time-dependent AUC), and risk group stratification. The net benefits of the nomogram at different threshold probabilities were quantified using decision curve analysis (DCA). RESULTS: The high-LDH group had significantly shorter OS compared to the low-LDH group (P = 0.016). Based on the SYSUCC cohort, three variables were shown to be significant factors for OS and were incorporated in the nomogram: LDH, histopathology, and dissemination. It showed good discrimination ability, with C-index of 0.789 (95% CI, 0.671-0.907). Additionally, the clinical usefulness of the nomogram was confirmed by calibration curves and time-dependent AUC. DCA further highlighted the potential of the nomogram to guide clinical treatment strategies for patients. Moreover, there was a significant difference in OS among patients categorized into different risk groups (P < 0.001). CONCLUSION: LDH levels may serve as a reliable predictor for assessing the therapeutic effect of chemoradiotherapy in GCT. The developed nomogram exhibits high accuracy in predicting survival outcomes, aiding in the classification of prognostic groups, and supporting informed clinical decision-making.

Biomarkers for Salvage Therapy in Testicular Germ Cell Tumors.

The outcome of metastatic testicular germ cell tumor patients has been dramatically improved by cisplatin-based chemotherapy combinations. However, up to 30% of patients with advanced disease relapse after first-line therapy and require salvage regimens, which include treatments with conventional-dose chemotherapy or high-dose chemotherapy with autologous stem cell transplantation. For these patients, prognosis estimation represents an essential step in the choice of medical treatment but still remains a complex challenge. The available histological, clinical, and biochemical parameters attempt to define the prognosis, but they do not reflect the tumor's molecular and pathological features and do not predict who will exhibit resistance to the several treatments. Molecular selection of patients and validated biomarkers are highly needed in order to improve current risk stratification and identify novel therapeutic approaches for patients with recurrent disease. Biomolecular biomarkers, including microRNAs, gene expression profiles, and immune-related biomarkers are currently under investigation in testicular germ cell tumors and could potentially hold a prominent place in the future treatment selection and prognostication of these tumors. The aim of this review is to summarize current scientific data regarding prognostic and predictive biomarkers for salvage therapy in testicular germ cell tumors.

Intracranial Germ Cell Tumors.

Intracranial germ cell tumors are rare tumors occurring in adolescents and young adults, which include germinomas and non-germinomatous type germ cell tumors (NGGCT). In the past few decades, cooperative trial groups in Europe and North America have developed successful strategies to improve survival outcomes and decrease treatment-related toxicities. New approaches to establishing diagnosis have deferred the need for radical surgery. The 5-year event-free survival (EFS) is above 90% and even patients who present with metastatic germinoma can still be cured with chemotherapy and craniospinal irradiation. The combination of surgery, chemotherapy, and radiation therapy is tailored to patients based on grouping and staging. For NGGCT, neoadjuvant chemotherapy followed by delayed surgery for residual disease and radiotherapy can yield a 5-year EFS of 70%. Further strategies should focus on reducing long-term complications while preserving high cure rates.

Intracranial germ cell tumors: a view of the endocrinologist.

Intracranial germ cell tumors (iGCTs) are rare malignant neoplasms that mainly affect children and adolescents. The incidence, clinical presentation, and prognosis of iGCTs exhibit high heterogeneity. Previous studies have primarily focused on eliminating tumors, reducing tumor recurrence, and improving survival rates, while neglecting the impact of the tumors and their treatment on neuroendocrine function. Throughout the entire course of the disease, neuroendocrine dysfunction may occur and is frequently overlooked by oncologists, neurosurgeons, and radiologists. Endocrinologists, however, are more interested in this issue and have varying priorities at different stages of the disease. From onset to the diagnostic phase, most patients with iGCTs may present with symptoms related to impaired neuroendocrine function, or even experience these symptoms as their first indication of the condition. Particularly, a minority of patients with sellar/suprasellar lesions may exhibit typical imaging features and elevated tumor markers long after the onset of initial symptoms. This can further complicate the diagnosis process. During the peritumor treatment phase, the neuroendocrine function shows dynamic changes and needs to be evaluated dynamically. Once diabetes insipidus and dysfunction of the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-thyroid axes occur, hormone replacement therapy should be administered promptly to ensure successful tumor treatment for the patient. Subsequently, during the long-term management phase after the completion of tumor treatment, the evaluation of growth and development as well as corresponding hormone replacement therapy are the most concerning and complex issues. Thus, this paper reviews the interest of endocrinologists in iGCTs at different stages.

Pineal/germ cell tumors and pineal parenchymal tumors.

INTRODUCTION: Pineal region tumors (PRTs) are tumors arising from the pineal gland and the paraspinal structures. These tumors are rare and heterogeneous that account for 2.8-10.1% and 0.6-3.2% of tumors in children and in all ages, respectively. Almost all types and subtypes of CNS tumors may be diagnosed in this region. These tumors come from cells of the pineal gland (pinealocytes and neuroglial cells), ectopic primordial germ cells (PGC), and cells from adjacent structures. Hence, PRTs are consisted of pineal parenchyma tumors (PPTs), germ cell tumors (GCTs), neuroepithelial tumors (NETs), other miscellaneous types of tumors, cystic tumors (epidermoid, dermoid), and pineal cyst in addition. The symptoms of PRTs correlate to the increased intracranial cranial pressure due to obstructive hydrocephalus and dorsal midbrain compression. The diagnostic imaging studies are mainly MRI of brain (with and without gadolinium) along with a sagittal view of whole spine. Serum and/or CSF AFP/ß-HCG helps to identify GCTs. The treatment of PRTs is consisted of the selection of surgical biopsy/resection, handling of hydrocephalus, neoadjuvant and/or adjuvant therapy according to age, tumor location, histopathological/molecular classification, grading of tumors, staging, and threshold value of markers (for GCTs) in addition. METHODS: In this article, we review the following focus points: 1. Background of pineal region tumors. 2. Pineal GCTs and evolution of management. 3. Molecular study for GCTs and pineal parenchymal tumors. 4. Review of surgical approaches to the pineal region. 5. Contribution of endoscopy. 6. Adjuvant therapy (chemotherapy, radiotherapy, and combination). 7. RESULTS: In all ages, the leading three types of PRTs in western countries were PPTs (22.7-34.8%), GCTs (27.3-34.4%), and NETs (17.2-28%). In children and young adults, the leading PRTs were invariably in the order of GCTs (40-80.5%), PPTs (7.6-21.6%), NETs (2.4-37.5%). Surgical biopsy/resection of PRTs is important for precision diagnosis and therapy. Safe resection with acceptable low mortality and morbidity was achieved after 1970s because of the advancement of surgical approaches, CSF shunt and valve system, microscopic and endoscopic surgery. Following histopathological diagnosis and classification of types and subtypes of PRTs, in PPTs, through molecular profiling, four molecular groups of pineoblastoma (PB) and their oncogenic driver were identified. Hence, molecular stratified precision therapy can be achieved. CONCLUSION: Modern endoscopic and microsurgical approaches help to achieve precise histopathological diagnosis and molecular classification of different types and subtypes of pineal region tumors for risk-stratified optimal, effective, and protective therapy. In the future, molecular analysis of biospecimen (CSF and blood) along with AI radiomics on tumor imaging integrating clinical and bioinformation may help for personalized and risk-stratified management of patients with pineal region tumors.

Comparative Analysis of the Embryonal Brain Tumors Based on Their Molecular Features.

Pediatric brain tumors currently show the highest incidence among solid childhood malignancies and, together with leukemia, are the leading cause of death from cancer in childhood. Embryonal brain tumors are the most common and frequent type of childhood brain cancer and are usually characterized by an extremely aggressive course of the disease with the worst outcomes in most cases. There is an urgent need for specific refined molecular diagnostics, which would help to develop personalized treatment. In the present review paper, the latest molecular characteristics of various classified forms of embryonal brain tumors were analyzed in detail. Overexpression of the MYC and MYCN genes is characteristic of many embryonal brain tumors, leading to enhanced cell proliferation and disturbances in the cell cycle. The functioning of the SWI2/SNF2 chromatin remodeling complex are distorted in such malignancies as well. Noteworthy, LIN28 and MYC discussed here are involved in the induction of pluripotency. We have to mention that molecular mechanisms underlying the development of embryonal brain tumors of the central nervous system (CNS) are still not well understood. Thus, it is important to uncover such mechanisms with the aim to provide a better prognosis of the course of disease and to create personalized therapy.

​Occult extracranial malignancy after complete remission of pineal mixed germ cell tumors: a rare case report and literature review.

BACKGROUND: ​Extracranial metastasis can occur in intracranial germ cell tumors (GCTs), but it is very rare. Recurrence or metastasis of non-germinomatous germ cell tumors (NGGCTs) is often accompanied by elevated tumor markers. ​Occult extracranial metastases or recurrences with negative markers are often difficult to detect in time, resulting in a very poor prognosis. CASE PRESENTATION: A 12-year-old boy was admitted to our institution with dizziness, headache, vomiting, and sleepiness. Magnetic resonance imaging (MRI) showed a pineal mass, accompanied by a significant increase in serum alpha-fetoprotein (AFP). The patient subsequently underwent total removal of the tumor. Pathology revealed that the tumor was a mixed GCT, consisting of mature teratoma, germinoma, and yolk sac tumor. Intracranial GCT achieved complete remission after intensive adjuvant chemotherapy and radiotherapy. Regular follow-up MRI revealed no recurrence of the intracranial tumor and continued monitoring of tumor markers revealed no abnormalities. ​Eight months later, the patient was readmitted due to progressive abdominal pain. Imaging and physical examination revealed abdominal occupation and lymphatic mass in the neck. He received salvage chemotherapy, anti-PD-1 immunotherapy, and palliative chemotherapy, but still developed multiple organ dysfunction syndromes (MODS) due to tumor progression and eventually died after one month. CONCLUSIONS: ​This profound case suggests that intracranial NGGCTs may develop occult extracranial malignancy, which can be very severe at the time of clinical symptoms and has an extremely poor prognosis. Therefore, in addition to tumor marker monitoring, regular follow-up with extracranial imaging may be warranted to detect extracranial tumors as early as possible, although perhaps not as frequently as with neuroimaging.