Human chorionic gonadotropin detection in cerebrospinal fluid of patients with a germinoma and its prognostic significance: assessment by using a highly sensitive enzyme immunoassay

A compact microfluidic laser-induced fluorescence immunoassay system using avalanche photodiode for rapid detection of alpha-fetoprotein

Alpha-fetoprotein (AFP), commonly employed for early diagnosis of liver cancer, serves as a biomarker for cancer screening and diagnosis. Combining the high sensitivity and specificity of fluorescence immunoassay (FIA), developing a low-cost and efficient immunoassay system for AFP detection holds significant importance in disease diagnosis. In this work, we developed a miniaturized oblique laser-induced fluorescence (LIF) immunoassay system, coupled with a microfluidic PMMA/paper hybrid chip, for rapid detection of AFP. The system employed an avalanche photodiode (APD) as the detector, and implemented multi-level filtering in the excitation light channel using the dichroic mirror and optical trap. At first, we employed the Savitzky-Golay filter and baseline off-set elimination methods to denoise and normalize the original data. Then the cutoff frequency of the low-pass filter and the reverse voltage of the APD were optimized to enhance the detection sensitivity of the system. Furthermore, the effect of laser power on the fluorescence excitation efficiency was investigated, and the sampling time during the scanning process was optimized. Finally, a four-parameter logistic (4PL) model was utilized to establish the concentration-response equation for AFP. The system was capable of detecting concentrations of AFP standard solution within the range of 1-500 ng/mL, with a detection limit of 0.8 ng/mL. The entire immunoassay process could be completed within 15 min. It has an excellent potential for applications in low-cost portable diagnostic instruments for the rapid detection of biomarkers.

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/β-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.

FUTURE DIRECTION

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.

Update on MRI in pediatric intracranial germ cell tumors-The clinical and radiological features

Intracranial germ cell tumors (iGCTs) are uncommon brain tumors that mainly occur in children. Differing in histology, location, and gender of the patients, iGCTs are often divided into germinomas and non-germinomatous germ cell tumors (NGGCTs). Early diagnosis and timely treatment are crucial to iGCTs, the subtypes of which have substantial variations. This review summarized the clinical and radiological features of iGCTs at different sites, and reviewed the recent advances in neuroimaging of iGCTs, which can help predict tumor subtypes early and guide clinical decision-making.

Clinical significance and pitfalls of human chorionic gonadotropin-related tumor markers for intracranial germinomas

PURPOSE

Measuring serum and cerebrospinal fluid human chorionic gonadotropin (hCG) is essential for the diagnosis of intracranial germ cell tumors. There are three types of hCG-related markers in clinical use: hCGβ, intact hCG, and total hCG. The best marker for the diagnosis of intracranial germ cell tumors, especially germinoma, is currently unknown. This study aimed to evaluate the usefulness of these hCG-related markers.

METHODS

We investigated 19 serum samples obtained from 6 patients with histologically diagnosed germinoma treated in our institute. Serum hCGβ, intact hCG, and total hCG values were measured before, during, and after treatment. Samples with hCG values above the lower limits were considered positive.

RESULTS

The positivity rates of serum hCGβ, intact hCG, and total hCG were 6% (1/17), 47% (7/15), and 42% (8/19), respectively, with the latter two having significantly higher positivity rates than hCGβ (p = 0.041). Both intact and total hCGs showed similar values. The median values of hCGβ, intact hCG, and total hCG before treatment were 0.1 ng/mL, 4.6 mIU/mL, and 4.5 mIU/mL, respectively.

CONCLUSION

Serum intact and total hCGs have higher detection rates than hCGβ in patients with germinoma using available commercial measurement tools.

Cerebrospinal Fluid biomarkers in pediatric brain tumors: A systematic review

Central nervous system (CNS) tumors are the leading cause of cancer death in pediatric patients. Though these tumors typically require invasive surgical procedures to diagnose, cerebrospinal fluid (CSF) liquid biopsy presents a potential method for rapid and noninvasive detection of markers of CNS malignancy. To characterize molecular biomarkers that can be used in the diagnosis, prognosis, and monitoring of pediatric cancer patients, a literature review was conducted in accordance with PRISMA guidelines. PubMed and EMBASE were searched for the terms biomarkers, liquid biopsy, cerebrospinal fluid, pediatric central nervous system tumor, and their synonyms. Studies including pediatric patients with CSF sampling for tumor evaluation were included. Studies were excluded if they did not have full text or if they were case studies, methodology reports, in languages other than English, or animal studies. Our search revealed 163 articles of which 42 were included. Proteomic, genomic, and small molecule markers associated with CNS tumors were identified for further analysis and development of detection tools.

Biomarkers for risk-based treatment modifications for CNS germ cell tumors: Updates on biological underpinnings, clinical trials, and future directions

CNS germ cell tumors (GCTs) preferentially occur in pediatric and adolescent patients. GCTs are located predominantly in the neurohypophysis and the pineal gland. Histopathologically, GCTs are broadly classified into germinomas and non-germinomatous GCTs (NGGCTs). In general, germinoma responds well to chemotherapy and radiation therapy, with a 10-year overall survival (OS) rate of approximately 90%. In contrast, NGGCTs have a less favorable prognosis, with a five-year OS of approximately 70%. Germinomas are typically treated with platinum-based chemotherapy and whole-ventricular radiation therapy, while mature teratomas can be surgically cured. Other NGGCTs require intensive chemotherapy with radiation therapy, including whole brain or craniospinal irradiation, depending on the dissemination status and protocols. Long-term treatment-related sequelae, including secondary neoplasms and cerebrovascular events, have been well recognized. These late effects have a tremendous impact in later life, especially since patients are mostly affected in childhood or young adults. Intending to minimize the treatment burden on patients, the identification of biomarkers for treatment stratification and evaluation of treatment response is of critical importance. Recently, tumor cell content in germinomas has been shown to be closely related to prognosis, suggesting that cases with low tumor cell content may be safely treated with a less intensive regimen. Among the copy number alterations, the 12p gain is the most prominent and has been shown to be a negative prognostic factor in NGGCTs. MicroRNA clusters (mir-371-373) were also revealed to be a hallmark of GCTs, demonstrating the potential for the application of liquid biopsy in the diagnosis and detection of recurrence. Recurrent mutations have been detected in the MAPK or PI3K pathways, most typically in KIT and MTOR and low genome-wide methylation has been demonstrated in germinoma; this most likely reflects the cell-of-origin primordial germ cells for this tumor type. These alterations can also be leveraged for liquid biopsies of cell-free DNA and may potentially be targeted for treatment in the future. Advancements in basic research will be translated into clinical practice and can directly impact patient management. Additional understanding of the biology and pathogenesis of GCTs will lead to the development of better-stratified clinical trials, ultimately resulting in improved treatment outcomes and a reduction in long-term treatment-related adverse effects.

Roles of Tumor Markers in Central Nervous System Germ Cell Tumors Revisited with Histopathology-Proven Cases in a Large International Cohort

The central nervous system germ cell tumor (CNS GCT) is a rare and incompletely understood disease. A major outstanding question in the 2015 consensus document for CNS GCT management was the utility and interpretation of the tumor markers human chorionic gonadotropin (HCG) and alpha fetoprotein (AFP) in the diagnosis of malignant non-germinomatous GCTs (hereafter NGGCTs) prior to treatment. In the current study, we assembled two geographically and ethnically different clinical cohorts from the Mayo Clinic (1988-2017) and the intracranial GCT Genome Analysis Consortium (iGCT Consortium) in Japan to address this question. Patients with both histopathological diagnosis and tumor markers available were eligible for inclusion (n = 162). Biopsy and surgical resection were performed in 85 and 77 cases, respectively. Among 77 resections, 35 demonstrated positivity for HCG, AFP, or both (45%). Seventeen of the marker-positive cases had no malignant non-germinomatous component identified on histopathology, but they were composed strictly of germinoma, teratoma, or both (49%). One embryonal carcinoma was the only marker-negative NGGCT in the study sample. Among 85 biopsies, 18 were marker positive (21%). Seven of these patients had no malignant non-germinomatous component on histopathology, suggesting the potential limitations of limited tissue sample volumes. Neither histopathological diagnosis nor tumor markers alone reliably diagnose NGGCTs due to the secretion of HCG and AFP by germinomas and teratomas. Treatment planning should incorporate integrated histopathological and laboratory-based diagnosis to optimize diagnostic and treatment strategies for this unusual and histologically heterogeneous tumor.

Case report: Fluctuating tumor markers in a boy with gonadotropin-releasing hormone-independent precocious puberty induced by a pineal germ cell tumor

GnRH-independent precocious puberty (GIPP) can be the presenting clinical picture experienced by patients with secreting germ cell tumor (GCT). Indeed, as luteinizing hormone (LH) and human chorionic gonadotropin (hCG) share identical α-subunits and similar β-subunits, an increased secretion of β-hCG may result in a precocious activation of Leydig cells. Though the co-occurrence of raised β-hCG levels and signs of precocious virilization usually prompts a complete oncological work-up, the diagnostic and therapeutic management of GCT-induced GIPP may be challenging. We report the case of a 6.2 year-old boy presenting with clinical and biochemical findings consistent with GIPP (discrepancy between overt virilization and pre-pubertal testicular volume, suppressed gonadotropins and remarkably raised testosterone). Brain imaging detected a bilobed cyst of the pineal gland, while serum and cerebrospinal baseline assessment initially ruled out raised alpha-fetoprotein or β-hCG levels. Nevertheless, a strict biochemical follow-up highlighted a fluctuant trend of tumor markers, with a more aggressive behavior and recurrent erections occurring as a result of unpredictable phases of raised testosterone and serum/cerebrospinal β-hCG, followed by sudden spontaneous decrease. Accordingly, a secreting pineal GCT was suspected. Given the fluctuating trend of tumor markers, surgery was initially kept on hold and a combined treatment with bicalutamide (androgen receptor blocker) and anastrozole (aromatase inhibitor) was undertaken in order to prevent the patient from experiencing further virilization and excessive bone age maturation. Subsequently, a progression in the size of the pineal tumor prompted surgical resection and a diagnosis of secreting GCT was histologically confirmed. Accordingly, the patient was started on adjuvant chemo- and radiotherapy. Antineoplastic treatment was followed by persistent and remarkable decrease of tumor markers and by a complete pubertal arrest. We reported the challenging diagnosis of a secreting pineal GCT in a patient with GIPP and a fluctuating trend of tumor markers, testosterone levels and associated clinical signs, hence prompting the indication for a systematic assessment and a strict monitoring whenever a patient with GnRH-independent precocious puberty shows clinical or radiological markers potentially consistent with a GCT.

Low tumor cell content predicts favorable prognosis in germinoma patients

Background

Germinoma preferentially occurs in pediatric and young adult age groups. Although they are responsive to treatment with chemotherapy and radiation, the treatment may cause long-term sequelae in their later lives. Here, we searched for clinical and histopathological features to predict the prognosis of germinoma and affect treatment response.

Methods

A total of 114 germinoma cases were included in the analysis. We investigated the association between clinical factors, tumor cell content, and progression-free survival (PFS).

Results

The tumor cell content was widely distributed from <5% to 90% in the specimens, with a median value of 50%. Female patients showed higher tumor cell content in the specimens (P = .002). Cases with lesions at atypical sites showed shorter PFS than those with lesions at other sites (P = .03). Patients with a higher tumor cell content (≥50%) showed shorter PFS than those with a lower tumor cell content (<50%) (P = .03). In multivariate analysis, tumor cell content was the only statistically significant prognostic factor (P = .04). Among the 7 cases treated with local radiation and chemotherapy, all 3 cases that recurred (2 outside of the radiation field, 1 unknown) had tumor cell content of ≥50% in the original specimen, whereas all 4 cases without recurrence had tumor cell contents of <50%.

Conclusions

We found that tumor cell content significantly affected the prognosis of germinomas. Although validation of these results using an independent and larger cohort is necessary, this potentially opens the possibility of leveraging this pathological factor in future clinical trials when stratifying the treatment intensity.

Management of children and young people with idiopathic pituitary stalk thickening, central diabetes insipidus, or both: a national clinical practice consensus guideline

Unexplained or idiopathic pituitary stalk thickening or central diabetes insipidus not only harbours rare occult malignancies in 40% of cases but can also reflect benign congenital defects. Between 2014 and 2019, a multidisciplinary, expert national guideline development group in the UK systematically developed a management flowchart and clinical practice guideline to inform specialist care and improve outcomes in children and young people (aged <19 years) with idiopathic pituitary stalk thickening, central diabetes insipidus, or both. All such cases of idiopathic pituitary stalk thickening and central diabetes insipidus require dynamic pituitary function testing, specialist pituitary imaging, measurement of serum β-human chorionic gonadotropin and alpha-fetoprotein concentrations, chest x-ray, abdominal ultrasonography, optometry, and skeletal survey for occult disease. Stalk thickening of 4 mm or more at the optic chiasm, 3 mm or more at pituitary insertion, or both, is potentially pathological, particularly if an endocrinopathy or visual impairment coexists. In this guideline, we define the role of surveillance, cerebrospinal fluid tumour markers, whole-body imaging, indications, timing and risks of stalk biopsy, and criteria for discharge. We encourage a registry of outcomes to validate the systematic approach described in this guideline and research to establish typical paediatric stalk sizes and the possible role of novel biomarkers, imaging techniques, or both, in diagnosis.

A clinical approach to parasellar lesions in the transition age

Many reviews have summarised the pathology and management of the parasellar region in adult patients, although an analysis of these aspects in the transition years, from puberty onset to the age of peak bone mass, has been lacking. A comprehensive search of English-language original articles, published from 2000 to 2020, was conducted in the MEDLINE database (December 2019 to March 2020). We selected all studies regarding epidemiology, diagnosis and management of the following parasellar lesions: germinoma, craniopharyngioma, Langerhans cell histiocytosis, optic glioma, hypothalamic hamartoma, tuber cinereum hamartoma, cranial chordoma, Rathke cleft cyst, hypophysitis and hypothalamitis during the transition age from childhood to adulthood. In the present review, we provide an overview of the principal parasellar lesions occurring in the transition age. Symptoms are usually a result of the mass effect of the lesions on nearby structures, as well as anterior pituitary deficits. Diabetes insipidus occurs frequently in these patients. In this age group, pubertal developmental disorders may be more evident compared to other stages of life. Parasellar lesions in the transition age mostly include neoplastic lesions such as germinomas, hamartomas, optic gliomas, craniopharyngiomas Langerhans cell histiocytosis and chordomas, and rarely inflammatory lesions (hypophysitis, hypothalamitis). There are limited data on the management of parasellar lesions in the transition age. Endocrine evaluation is crucial for identifying conditions that require hormonal treatment so that they can be treated early to improve the quality of life of the individual patient in this complex age range. The clinical approach to parasellar lesions involves a multidisciplinary effort.

Diagnostic Capability of Cerebrospinal Fluid-Placental Alkaline Phosphatase Value in Intracranial Germ Cell Tumor

OBJECTIVE

Most types of intracranial germ cell tumors (IGCTs) are sensitive to chemoradiation. However, biopsy specimens are usually small and thus cannot be used for obtaining an accurate pathological diagnosis. Recently, the cerebrospinal fluid (CSF) placental alkaline phosphatase (PLAP) value has been considered a new biomarker of IGCTs. The present study aimed to evaluate the discriminatory characteristics of the CSF-PLAP value upon diagnosis and at the time of recurrence in patients with IGCTs.

METHODS

Between 2015 and 2019, this study included 37 patients with tumors located in the intraventricular and/or periventricular region. The CSF-PLAP level was assessed before the patients received any treatment. The PLAP level was evaluated during and after first-line chemoradiotherapy in 7 patients with IGCTs. The CSF-PLAP values were compared according to histological diagnosis, and the correlation between these values and radiographical features was assessed. The CSF-PLAP values of 6 patients with IGCTs with suspected recurrence were evaluated based on neuroimaging findings.

RESULTS

The CSF-PLAP values were significantly higher in patients with IGCTs than in those with other types of brain tumor (n = 19 vs. 18; median: 359.0 vs. <8.0 pg/mL). The specificity and sensitivity were 88 and 95%, respectively, with a cutoff value of 8.0 pg/mL. In patients with IGCT, the CSF-PLAP value was higher in patients with germinoma than in those with nongerminomatous germ cell tumors (n = 12 vs. 7; median: 415.0 vs. 359.0 pg/mL). Regarding the time course, the CSF-PLAP value decreased to below the detection limit after the reception of first-line chemoradiotherapy in all 7 patients. A significant correlation was observed between the initial CSF-PLAP value and the tumor reduction volume after receiving first-line chemoradiotherapy (p < 0.0003, R2 = 0.6165, logY = 1.202logX - 1.727). Among the patients with suspected IGCT recurrence (n = 6), the CSF-PLAP value was high in patients with recurrence (n = 3; median: 259.0 pg/mL), and that in patients (n = 3) without recurrence was below the lower detection limit.

CONCLUSIONS

The CSF-PLAP level is a useful biomarker during the initial diagnosis of IGCTs and at the time of recurrence. It may be associated with the volume of germinomatous components of tumors.

Integrated clinical, histopathological, and molecular data analysis of 190 central nervous system germ cell tumors from the iGCT Consortium

BACKGROUND

We integrated clinical, histopathological, and molecular data of central nervous system germ cell tumors to provide insights into their management.

METHODS

Data from the Intracranial Germ Cell Tumor Genome Analysis (iGCT) Consortium were reviewed. A total of 190 cases were classified as primary germ cell tumors (GCTs) based on central pathological reviews.

RESULTS

All but one of the cases that were bifocal (neurohypophysis and pineal glands) and cases with multiple lesions including neurohypophysis or pineal gland were germinomas (34 of 35). Age was significantly higher in patients with germinoma than other histologies. Comparison between tumor marker and histopathological diagnoses showed that 18.2% of histopathologically diagnosed germinomas were marker positive and 6.1% of non-germinomatous GCTs were marker negative, suggesting a limitation in the utility of markers or histopathology alone using small specimens for diagnosis. Comparison between local and central histopathological diagnoses revealed a discordance of 12.7%. Discordance was significantly less frequent in biopsy cases, implying difficulty in detecting all histopathological components of heterogeneous GCTs. Germinomas at the typical sites (neurohypophysis or pineal gland) showed a better progression-free survival than those at atypical sites (P = 0.03). A molecular clinical association study revealed frequent mitogen-activated protein kinase (MAPK) pathway mutations in males (51.4% vs 14.3%, P = 0.007), and phosphatidylinositol-3 kinase/mammalian target of rapamycin (PI3K/mTOR) pathway mutations in basal ganglia cases (P = 0.004). Basal ganglia cases also had frequent chromosomal losses. Some chromosomal aberrations (2q, 8q gain, 5q, 9p/q, 13q, 15q loss) showed potential prognostic significance.

CONCLUSIONS

The in-depth findings of this study regarding clinical and molecular heterogeneity will increase our understanding of the pathogenesis of this enigmatic tumor.

Suprasellar germinoma with hypopituitarism in an 18-year old man: A case report and review of literature

An 18 year old patient was presented to the ophtalmology outpatient clinic with blurrred vision, headache and fatigue for 6 months. Ophtalmological examination showed loss of visual acuity in the left eye and decreased in the right eye and bilateral optic atrophy. Further physical examination pointed out delayed sexual development. Hypopituitarism was observed in endocrinological examination. Brain magnetic resonance imaging (MRI) demonstrated contrast enhancing mass lesion at suprasellar region with involvement of posterior perimesencephalic cisternal region. The mass resected by craniotomy and pathology showed germinoma. Afterwards he received systemic chemotherapy with bleomisin, etoposide, cisplatin for 4 cycles followed by cranial radiotherapy with 30.6 Gy with a boost to the primary tumor at a dose of 19.8 Gy. On his follow-up MRI, there are no signs of residual tumor nor tumor recurrence. His final examination reveals slightly increased visual acuity in the right eye and he continued to take hydrocortisone and L-thyroxin. After one year follow-up, human chorionic gonadotropin (hCG) alpha treatment was started for sexual development. Here in, we present a case with suprasellar germinoma in the context of the review of the literature.

Suprasellar Germinomas: 2 Case Reports and Literature Review

BACKGROUND

Germinomas are rare malignant central nervous system tumors, a type of germ cell tumor, according to the 2016 World Health Organization Classification of Brain Tumors. Most of these tumors develop along the midline, most often from the pineal gland, followed by tumors arising in the suprasellar cisterns. Suprasellar germinomas commonly manifest with diabetes insipidus, visual impairment, and hypothalamic-pituitary failure. We present a literature review from the PubMed database and report 2 cases of suprasellar germinomas.

CASE DESCRIPTION

Both pediatric patients presented with progressive visual loss; one did not show endocrinologic impairment, and the other presented with hypothyroidism, diabetes insipidus, and generalized edema. Magnetic resonance imaging showed expansive suprasellar masses in both cases, confirmed as germinomas at histopathologic examination. The patients were treated with the same surgical approach, although their outcomes were different because of endocrinologic and post surgical complications.

CONCLUSIONS

Suprasellar germinomas are highly curable lesions when diagnosed early. The treatment remains controversial and should be individualized, but the association of chemotherapy and radiotherapy allows reduce adverse effects and shows great results.