Molecular and cellular pathogenesis of adamantinomatous craniopharyngioma

The EMT status in the primary tumor of adamantinomatous craniopharyngioma predict postoperative recurrence in children

INTRODUCTION

Adamantinomatous craniopharyngiomas (ACP) are rare epithelial tumors, which by the WHO are classified as non-malignant tumors. Despite radical tumor regression, almost 57% of patients develop a craniopharyngioma recurrence. The pathogenesis of epithelial cancers involves a process called epithelial-mesenchymal transition (EMT), which is involved in tumor progression and its invasion, and the loss of E-cadherin is crucial for this process. Undoubtedly, EMT also plays a role in the progression of ACP, but there are no studies that would examine its role in predicting postoperative tumor recurrence. Therefore, in our study, we aimed to compare the expression of EMT inducers and their markers, namely E-cadherin and vimentin, in material from two groups of pediatric patients, first with postoperative ACP relapse and second without relapse.

METHODS

A total of 35 formalin-fixed, paraffin-embedded tissue blocks of pediatric patients (19 girls and 16 boys, from 2 to 17 years old) were included. The material was collected during craniopharyngioma resection in the years 2000-2019 and after then examined by the Department of Pathomorphology. Gene expression analysis was done using qRT-PCR.

RESULTS

In the studied group of 35 patients, high levels of E-cad and low levels of vimentin expression were found in patients who did not experience relapse (n = 25, p < 0.0001). The opposite was observed in patients who experienced a recurrence (n = 10, p < 0.0001). In contrast, analysis of the recurrent tissue itself showed low levels of vimentin and re-expression of E-cadherin (n = 10, p < 0.0001). Furthermore, our study shows that Snail is a key inducer of EMT in ACP.

CONCLUSION

We believe that the evaluation of the EMT profile in ACP could be a prognostic marker for predicting tumor recurrence in children, which would certainly contribute to a better prognosis for these patients.

Endoscopic endonasal resection of a craniopharyngioma in a 23-month-old patient: illustrative case

BACKGROUND

Treatment of pediatric craniopharyngioma requires a multidisciplinary approach to counsel patients and families on the spectrum of treatment options, including biopsy, radiation, and/or resection. Gross-total resection can avoid radiation and its long-term comorbidities. In very young patients, this is of particular importance but is especially challenging because of anatomical considerations.

OBSERVATIONS

A 23-month-old boy was found to have a partially calcified and cystic sellar and suprasellar mass. A fully endoscopic endonasal transtuberculum and transsellar approach was performed for gross-total resection of a subdiaphragmatic adamantinomatous craniopharyngioma. Postoperatively, the patient was diagnosed with panhypopituitarism with diabetes insipidus, though without other hypothalamic dysfunction or new visual deficits. To date, there is no evidence of tumor recurrence.

LESSONS

In a high-volume center with an experienced multidisciplinary skull base team, endoscopic endonasal approaches to sellar and suprasellar pathology in children younger than 2 years can be safely performed. A smaller nasal cavity and lack of sinus aeration necessitate wide exposure via bone removal and complete opening of the sinuses to enable an adequate working corridor to perform not only tumor resection but also reconstruction. Safe gross-total resection can avoid, or at least delay, radiation and its long-term morbidity when performed in a developing child. https://thejns.org/doi/10.3171/CASE24209.

Single-cell and spatial sequencing identifies senescent and germinal tumor cells in adamantinomatous craniopharyngiomas

Adamantinomatous craniopharyngioma (ACP) is a clinically aggressive tumor without effective treatment method. Previous studies proposed a paracrine tumorigenesis model, in which oncogenic β-catenin induces senescence in pituitary stem cells and the senescent cells lead the formation of paracrine tumors through secretion of pro-tumorigenic factors. However, there lacks characterization on senescent cells in ACPs. Here, we profiled 12 ACPs with single-cell RNA and TCR-sequencing to elucidate the cellular atlas in ACPs and 3 of them were also subject to spatial sequencing to localize different subpopulations of the tumor cells. In total, we obtained the transcriptome profiles of 70,682 cells. Tumor cells, which were unambiguously identified through the cellular mutation status of the driver CTNNB1 mutations, were clustered into 6 subsets. The whorl-like cluster (WC) cells show distinct molecular features from the other tumor cells and the palisading epithelium (PE) cells consists of a proliferating subset. Other than typical PE and WC, we identified two novel subpopulations of the tumor cells. In one subpopulation, the cells express a high level of cytokines, e.g., FDCSP and S100A8/A9, and are enriched with the senescence-associated secretory phenotype (SASP) factors. Hematoxylin and eosin staining reveals that these SASP cells lack an ordered structures and their nuclei are elongated. In the other subpopulation, the cell sizes are small and they are tightly packed together with an unusual high density expressing a high level of mitochondrial genes (median 10.9%). These cells are the origin of the tumor developmental trajectories revealed by RNA velocity and pseudo-time analysis. Single-cell RNA and TCR analysis reveals that some ACPs are infiltrated with clonally expanded cytotoxic T cells. We propose a hypothesis that WC and PE are formed via different negative regulation mechanisms of the overactivated WNT/β-catenin signaling which provides a new understanding on the tumorigenesis of ACPs. The study lays a foundation for future studies on targeting senescent cells in ACPs with senolytic compounds or other therapeutic agents.

Multiomics integration-based immunological characterizations of adamantinomatous craniopharyngioma in relation to keratinization

Although adamantinomatous craniopharyngioma (ACP) is a tumour with low histological malignancy, there are very few therapeutic options other than surgery. ACP has high histological complexity, and the unique features of the immunological microenvironment within ACP remain elusive. Further elucidation of the tumour microenvironment is particularly important to expand our knowledge of potential therapeutic targets. Here, we performed integrative analysis of 58,081 nuclei through single-nucleus RNA sequencing and spatial transcriptomics on ACP specimens to characterize the features and intercellular network within the microenvironment. The ACP environment is highly immunosuppressive with low levels of T-cell infiltration/cytotoxicity. Moreover, tumour-associated macrophages (TAMs), which originate from distinct sources, highly infiltrate the microenvironment. Using spatial transcriptomic data, we observed one kind of non-microglial derived TAM that highly expressed GPNMB close to the terminally differentiated epithelial cell characterized by RHCG, and this colocalization was verified by asmFISH. We also found the positive correlation of infiltration between these two cell types in datasets with larger cohort. According to intercellular communication analysis, we report a regulatory network that could facilitate the keratinization of RHCG+ epithelial cells, eventually causing tumour progression. Our findings provide a comprehensive analysis of the ACP immune microenvironment and reveal a potential therapeutic strategy base on interfering with these two types of cells.

Exploration of the shared pathways and common biomarker in adamantinomatous craniopharyngioma and type 2 diabetes using integrated bioinformatics analysis

Craniopharyngiomas are rare tumors of the central nervous system that typically present with symptoms such as headache and visual impairment, and those reflecting endocrine abnormalities, which seriously affect the quality of life of patients. Patients with craniopharyngiomas are at higher cardiometabolic risk, defined as conditions favoring the development of type 2 diabetes and cardiovascular disease. However, the underlying common pathogenic mechanisms of craniopharyngiomas and type 2 diabetes are not clear. Especially due to the difficulty of conducting in vitro or in vivo experiments on craniopharyngioma, we thought the common pathway analysis between craniopharyngioma and type 2 diabetes based on bioinformatics is a powerful and feasible method. In the present study, using public datasets (GSE94349, GSE68015, GSE38642 and GSE41762) obtained from the GEO database, the gene expression associated with adamantinomatous craniopharyngioma, a subtype of craniopharyngioma, and type 2 diabetes were analyzed using a bioinformatic approach. We found 11 hub genes using a protein-protein interaction network analysis. Of these, seven (DKK1, MMP12, KRT14, PLAU, WNT5B, IKBKB, and FGF19) were also identified by least absolute shrinkage and selection operator analysis. Finally, single-gene validation and receptor operating characteristic analysis revealed that four of these genes (MMP12, PLAU, KRT14, and DKK1) may be involved in the common pathogenetic mechanism of adamantinomatous craniopharyngioma and type 2 diabetes. In addition, we have characterized the differences in immune cell infiltration that characterize these two diseases, providing a reference for further research.

Multi-omics analysis of adamantinomatous craniopharyngiomas reveals distinct molecular subgroups with prognostic and treatment response significance

BACKGROUND

Adamantinomatous craniopharyngioma (ACP) is the commonest pediatric sellar tumor. No effective drug is available and interpatient heterogeneity is prominent. This study aimed to identify distinct molecular subgroups of ACP based on the multi-omics profiles, imaging findings, and histological features, in order to predict the response to anti-inflammatory treatment and immunotherapies.

METHODS

Totally 142 Chinese cases diagnosed with craniopharyngiomas were profiled, including 119 ACPs and 23 papillary craniopharyngiomas. Whole-exome sequencing (151 tumors, including recurrent ones), RNA sequencing (84 tumors), and DNA methylome profiling (95 tumors) were performed. Consensus clustering and non-negative matrix factorization were used for subgrouping, and Cox regression were utilized for prognostic evaluation, respectively.

RESULTS

Three distinct molecular subgroups were identified: WNT, ImA, and ImB. The WNT subgroup showed higher Wnt/β-catenin pathway activity, with a greater number of epithelial cells and more predominantly solid tumors. The ImA and ImB subgroups had activated inflammatory and interferon response pathways, with enhanced immune cell infiltration and more predominantly cystic tumors. Mitogen-activated protein kinases (MEK/MAPK) signaling was activated only in ImA samples, while IL-6 and epithelial-mesenchymal transition biomarkers were highly expressed in the ImB group, mostly consisting of children. The degree of astrogliosis was significantly elevated in the ImA group, with severe finger-like protrusions at the invasive front of the tumor. The molecular subgrouping was an independent prognostic factor, with the WNT group having longer event-free survival than ImB (Cox, P = 0.04). ImA/ImB cases were more likely to respond to immune checkpoint blockade (ICB) therapy than the WNT group ( P <0.01). In the preliminary screening of subtyping markers, CD38 was significantly downregulated in WNT compared with ImA and ImB ( P = 0.01).

CONCLUSIONS

ACP comprises three molecular subtypes with distinct imaging and histological features. The prognosis of the WNT type is better than that of the ImB group, which is more likely to benefit from the ICB treatment.

Correlations between the expression of molecules in the TGF-β signaling pathway and clinical factors in adamantinomatous craniopharyngiomas

Objective

To investigate the clinical and pathological factors associated with preoperative hypothalamus invasion and postoperative outcomes of adamantinomatous craniopharyngiomas (ACPs) after the expanded endonasal approach (EEA) resection.

Methods

Ninety-three specimens of ACPs, consisting of 71 primary and 22 recurrent tumors, were investigated for the expression of TGF-β1, SMAD2, SMAD3, and β-catenin by immunohistochemistry staining. The clinical information of relevant patients, including the extent of resection, hypothalamus invasion, endocrinopathy, complications, and prognosis, was reviewed. The relationships between the expression of these immunopathological markers and clinical factors were analyzed.

Results

Endocrinological dysfunctions were more common in recurrent patients and primary patients with hypothalamus invasion in the comparisons. For recurrent patients, the rate of gross total resection (GTR) was significantly lower than for primary patients (63.6% vs. 90.1%, P = 0.007). According to radiological and intraoperative findings, invasive ACPs (IACPs) included 48 (67.6%) cases in primary tumors. The expression of TGF-β1 and β-catenin was significantly higher in recurrent tumors (P = 0.021 and P = 0.018, respectively) and IACPs (P = 0.008 and P = 0.004, respectively). The expression level of TGF-β1 was associated with hypothalamus involvement (Puget grade, P = 0.05; Vile grade, P = 0.002), postoperative endocrinopathy (P = 0.01), and pituitary stalk preservation (P = 0.008) in primary patients. In addition, the extent of resection, treatment history, hypothalamic invasion, and level of TGF-β1 expression had significant influences on tumor recurrence/progression after surgery separately.

Conclusion

Our study demonstrated the potential role of TGF-β1 in the regulation of hypothalamus invasion in ACPs and the prediction of prognosis after EEA surgery. The TGF-β signaling pathway may represent a crucial mechanism in the aggressive behavior and progression of ACPs.

Transcription Factor GLI1 Induces IL-6-Mediated Inflammatory Response and Facilitates the Progression of Adamantinomatous Craniopharyngioma

Adamantinomatous craniopharyngioma (ACP) is a neuroendocrine tumor whose pathogenesis remains unclear. This study investigated the role of glioma-associated oncogene family zinc finger 1 (GLI1), a transcription factor in the sonic hedgehog (SHH) signaling pathway, in ACP. We discovered that GLI1 regulates the expression of IL-6, thereby triggering inflammatory responses in ACP and influencing the tumor's progression. Analyzing the Gene Expression Omnibus (GEO) database chip GSE68015, we found that GLI1 is overexpressed in ACP, correlating positively with the spite of ACP and inflammation markers. Knockdown of GLI1 significantly inhibited the levels of tumor necrosis factor α, interleukin-6 (IL-6), and IL-1β in ACP cells, as well as cell proliferation and migration. We further identified a binding site between GLI1 and the promoter region of IL-6, demonstrating that GLI1 can enhance the expression of IL-6. These findings were verified in vivo, where activation of the SHH pathway significantly promoted GLI1 and IL-6 expressions in nude mice, inducing inflammation and tumor growth. Conversely, GLI1 knockdown markedly suppressed these processes. Our study uncovers a potential molecular mechanism for the occurrence of inflammatory responses and tumor progression in ACP.

Pediatric diencephalic tumors: a constellation of entities and management modalities

The diencephalon is a complex midline structure consisting of the hypothalamus, neurohypophysis, subthalamus, thalamus, epithalamus, and pineal body. Tumors arising from each of these diencephalic components differ significantly in terms of biology and prognosis. The aim of this comprehensive review is to describe the epidemiology, clinical symptoms, imaging, histology, and molecular markers in the context of the 2021 WHO classification of central nervous system neoplasms. We will also discuss the current management of each of these tumors.

Expression of S100A9 in adamantinomatous craniopharyngioma and its association with wet keratin formation

Wet keratin is a hallmark of adamantinomatous craniopharyngioma (ACP), which is frequently infiltrated by inflammatory cells. S100 calcium-binding protein A9 (S100A9) has been confirmed to play a decisive role in the development of inflammation. However, the relationship between wet keratin (keratin nodules) and S100A9 in ACP is poorly understood. The objective of the present study was to explore the expression of S100A9 in ACP and its association with wet keratin formation. Immunohistochemistry and immunofluorescence were used to detect the expression of S100A9, β-catenin and Ki67 in 46 cases of ACP. A total of three online databases were used to analyze S100A9 gene expression and protein data. The results revealed that S100A9 was primarily expressed in wet keratin and some intratumoral and peritumoral cells, and its expression in wet keratin was upregulated in the high inflammation group (P=1.800x10^-3). In addition, S100A9 was correlated with the degree of inflammation (r=0.6; P=7.412x10^-3) and the percentage of Ki67-positive cells (r=0.37; P=1.000x10^-2). In addition, a significant correlation was noted between the area of wet keratin and the degree of inflammation (r=0.51; P=2.500x10^-4). In conclusion, the present study showed that S100A9 was upregulated in ACP and may be closely associated with wet keratin formation and the infiltration of inflammatory cells in ACP.

Single-cell RNA sequencing highlights intratumor heterogeneity and intercellular network featured in adamantinomatous craniopharyngioma

Despite improvements in microscopically neurosurgical techniques made in recent years, the prognosis of adamantinomatous craniopharyngioma (ACP) is still unsatisfactory. Little is known about cellular atlas and biological features of ACP. Here, we carried out integrative analysis of 44,038 single-cell transcriptome profiles to characterize the landscape of intratumoral heterogeneity and tumor microenvironment (TME) in ACP. Four major neoplastic cell states with distinctive expression signatures were defined, which further revealed the histopathological features and elucidated unknown cellular atlas of ACP. Pseudotime analyses suggested potential evolutionary trajectories between specific neoplastic cell states. Notably, a distinct oligodendrocyte lineage was identified in ACP, which was associated with immunological infiltration and neural damage. In addition, we described a tumor-centric regulatory network based on intercellular communication in TME. Together, our findings represent a unique resource for deciphering tumor heterogeneity of ACP, which will improve clinical diagnosis and treatment strategies.

The molecular pathogenesis of craniopharyngiomas

Research from the last 20 years has provided important insights into the molecular pathogenesis of craniopharyngiomas (CPs). Besides the well-known clinical and histological differences between the subtypes of CPs, adamantinomatous (ACP) and papillary (PCP) craniopharyngiomas, other molecular differences have been identified, further elucidating pathways related to the origin and development of such tumors. The present minireview assesses current knowledge on embryogenesis and the genetic, epigenetic, transcriptomic, and signaling pathways involved in the ACP and PCP subtypes, revealing the similarities and differences in their profiles. ACP and PCP subtypes can be identified by the presence of mutations in CTNNB1 and BRAF genes, with prevalence around 60% and 90%, respectively. Therefore, β-catenin accumulates in the nucleus-cytoplasm of cell clusters in ACPs and, in PCPs, cell immunostaining with specific antibody against the V600E-mutated protein can be seen. Distinct patterns of DNA methylation further differentiate ACPs and PCPs. In addition, research on genetic and epigenetic changes and tumor microenvironment specificities have further clarified the development and progression of the disease. No relevant transcriptional differences in ACPs have emerged between children and adults. In conclusion, ACPs and PCPs present diverse genetic signatures and each subtype is associated with specific signaling pathways. A better understanding of the pathways related to the growth of such tumors is paramount for the development of novel targeted therapeutic agents.

Molecular biological features of cyst wall of adamantinomatous craniopharyngioma

The molecular biological differences between cyst walls and those in solid bodies are the foundation of the outcomes. In this study, the CTNNB1 mutations were confirmed by DNAsequencing; CTNNB1 expression levels were detected by PCR; the differences between solid bodies and cyst walls in proliferative capacity and tumor stem cell niches were assessed by immunohistochemistry; the effect of the residual cyst wall on recurrence was assessed by follow-up. Mutations in the CTNNB1 in the cyst wall and the solid body were identical in each case. No differences were found in the transcriptional level of CTNNB1 between the cyst walls and the solid bodies (P = 0.7619). The cyst wall showed a pathological structure similar to the solid body. Proliferative capacity of cyst walls was stronger than that of solid body (P = 0.0021), and β-catenin nuclear positive cells (cell clusters) in cyst walls were more than that in solid tumor (P = 0.0002). The retrospective 45 ACPs showed residual cyst wall was significantly associated with tumor recurrence or regrowth (P = 0.0176). Kaplan-Meier analysis showed there was a significant difference in the prognosis between GTR and STR (P < 0.0001).The cyst wall of ACP contained more tumor stem cell niches which could lead to the recurrence. According to the above-mentioned, a special attention to the management of the cyst wall should be paid.

Primary pilocytic astrocytoma of the cerebellopontine angle in pediatric patient with neurofibromatosis type 1: a case report

Background

Cerebellopontine angle tumor (CPA) in pediatrics is rare as compared to adults. We describe a case of pediatric pilocytic astrocytoma presented as a right CPA mass with a concurrent clinical diagnosis of neurofibromatosis type 1 (NF1).

Case presentation

A 14-year-old boy with a newly diagnosed hypertension presented with a short history of headache and blurring vision. Neurological examination revealed bilateral papilloedema, partial right third nerve palsy and mild sensorineuronal hearing deficits. Skin examination identified multiple café au lait spots with cutaneous neurofibromas. Preoperative neuroimaging suggested the diagnosis of an extraaxial CPA mass consistent with meningioma, with obstructive hydrocephalus. A left ventriculoperitoneal shunt was inserted and the child was subjected for a suboccipital retrosigmoid approach for tumor resection. The histopathological features, however, were typical for pilocytic astrocytoma.

Conclusions

A careful evaluation of the clinical presentation and radiological images of CPA lesions is necessary prior to surgical embarkment. To the best of our knowledge, this case is the first report of pilocytic astrocytoma in the CPA in pediatric with NF1.

Hypothalamic syndrome

Hypothalamic syndrome (HS) is a rare disorder caused by disease-related and/or treatment-related injury to the hypothalamus, most commonly associated with rare, non-cancerous parasellar masses, such as craniopharyngiomas, germ cell tumours, gliomas, cysts of Rathke's pouch and Langerhans cell histiocytosis, as well as with genetic neurodevelopmental syndromes, such as Prader-Willi syndrome and septo-optic dysplasia. HS is characterized by intractable weight gain associated with severe morbid obesity, multiple endocrine abnormalities and memory impairment, attention deficit and reduced impulse control as well as increased risk of cardiovascular and metabolic disorders. Currently, there is no cure for this condition but treatments for general obesity are often used in patients with HS, including surgery, medication and counselling. However, these are mostly ineffective and no medications that are specifically approved for the treatment of HS are available. Specific challenges in HS are because the syndrome represents an adverse effect of different diseases, and that diagnostic criteria, aetiology, pathogenesis and management of HS are not completely defined.

Endoscopic Endonasal Transsphenoidal Surgery for Recurrent Craniopharyngiomas

Object

Although revision surgery for recurrent craniopharyngiomas is more challenging than primary surgery and often accompanies a higher risk of death and complications, endoscopic endonasal transsphenoidal surgery (EETS) is sometimes still an effective and reliable treatment option. In this study, we introduced the surgical outcomes of EETS for recurrent craniopharyngiomas and summarized the surgical experiences.

Methods

Between 2014 and 2018, 28 patients with recurrent craniopharyngiomas underwent 29 EETS in our department. We regarded the patient undergoing two EETS as two independent patients in statistical analysis. Of the 29 patients, 16 had undergone 1 previous surgery, 10 had undergone 2 previous surgeries, and the remaining 3 patients had undergone 3 surgeries. The extent of resection, visual and endocrine outcomes, and complications of all the patients were collected and analyzed.

Results

Gross total resection was accomplished in 16 patients (55.17%), subtotal resection in 11 patients (37.93%), and partial resection in 2 patients (6.9%). Among the 22 patients with preoperative visual acuity and visual field impairment, some degree of vision improvement was observed in 18 patients, 3 patients were without visual change, and perpetual deterioration of vision occurred in one patient. The remaining six patients had normal vision before and after surgery. Postoperative endocrine tests showed that, among five patients with normal preoperative pituitary hormone function, only one patient still had normal pituitary hormone function and the other four patients had one or more hypothalamic-pituitary axes involved. None of the patients with preoperative endocrine dysfunction had endocrine function improved. Diabetes insipidus was observed in six new cases postoperatively. Cerebrospinal fluid (CSF) leakage occurred in 1 patient. One patient had bacterial meningitis, which was cured with antibiotics and a lumbar drain. No serious morbidity and mortality occurred in all patients.

Conclusions

For recurrent craniopharyngiomas, a personalized treatment plan should be developed according to the tumor characteristics and the patient's situation. There is no omnipotent method to be used for all patients. The EETS still is a safe and effective way to treat recurrent craniopharyngiomas in appropriate patients.

A Novel Immune Classification for Predicting Immunotherapy Responsiveness in Patients With Adamantinomatous Craniopharyngioma

Adamantinomatous craniopharyngioma (ACP) is the most common tumor of the sellar region in children. The aggressive behavior of ACP challenges the treatment for it. However, immunotherapy is rarely studied in ACP. In this research, we performed unsupervised cluster analysis on the 725 immune-related genes and arrays of 39 patients with ACP patients in GSE60815 and GSE94349 databases. Two novel immune subtypes were identified, namely immune resistance (IR) subtype and immunogenic (IG) subtype. Interestingly, we found that the ACPs with IG subtype (34.78%, 8/23) were more likely to respond to immunotherapy than the ACPs with IR subtype (6.25%, 1/16) via tumor immune dysfunction and exclusion (TIDE) method. Simultaneously, the enrichment analysis indicated that the differentially expressed genes (DEGs) (p < 0.01, FDR < 0.01) of the IG subtype were chiefly involved in inflammatory and immune responses. However, the DEGs of the IR subtype were mainly involved in RNA processing. Next, immune infiltration analysis revealed a higher proportion of M2 macrophage in the IG subtype than that in the IR subtype. Compared with the IR subtype, the expression levels of immune checkpoint molecules (PD1, PDL1, PDL2, TIM3, CTLA4, Galectin9, LAG3, and CD86) were significantly upregulated in the IG subtype. The ssGSEA results demonstrated that the biofunction of carcinogenesis in the IG subtype was significantly enriched, such as lymphocyte infiltration, mesenchymal phenotype, stemness maintenance, and tumorigenic cytokines, compared with the IR subtype. Finally, a WDR89 (the DEG between IG and IR subtype)-based nomogram model was constructed to predict the immune classification of ACPs with excellent performance. This predictive model provided a reliable classification assessment tool for clinicians and aids treatment decision-making in the clinic.

Update on management of craniopharyngiomas

PURPOSE/INTRODUCTION

Craniopharyngiomas are locally-aggressive tumors arising along the hypothalamic-pituitary axis. Treatment is nuanced as a result of their proximity and adherence to vital neurovascular structures and responsiveness to surgery, radiation and, in some cases, chemotherapy.

METHODS

We reviewed the literature discussing the current state of knowledge regarding craniopharyngioma biology and therapy.

RESULTS

Recent advances in endoscopic endonasal surgery (EEA) have made surgery a safer and more effective option. While cure may be achieved with gross total resection (GTR), when felt to be too risky, a subtotal resection followed by radiation is often a more prudent strategy, particularly in children with hypothalamic invasion. Data on long-term outcome are mostly derived from older studies in which a craniotomy, rather than EEA, was performed. Long-term EEA outcome studies are lacking. Enhanced knowledge of the biological basis of papillary CPs has led to novel medical treatments for BRAFv^600E variants that appear to be effective.

CONCLUSION

Endoscopic technology has improved surgical results for craniopharyngiomas and expanded the indications for the transsphenoidal approach. The goal of CP surgery goal is maximal safe resection to achieve cure, but subtotal resection and radiation may be equally effective. Early diagnosis of specific variants will facilitate enrollment in promising medical trials.

Evaluation of Long-Term Outcomes and Toxicity After Stereotactic Phosphorus-32-Based Intracavitary Brachytherapy in Patients With Cystic Craniopharyngioma

PURPOSE

Interstitial brachytherapy based on phosphorus-32 (P-32) has an established role as a minimally invasive treatment modality for patients with cystic craniopharyngioma. However, reporting on long-term outcomes with toxicity profiles for large cohorts is lacking in the literature. The purpose of this study is therefore to evaluate the long-term visual, endocrinal, and neurocognitive functions in what is the largest patient series having received this treatment to date.

METHODS AND MATERIALS

We retrospectively evaluated 90 patients with cystic craniopharyngiomas who were treated with stereotactic intracavitary brachytherapy between 1998 and 2010. Colloidal activity of injected radioisotope P-32 was based on an even distribution within the tumor. After treatment, patients were followed-up for a minimum of 5 years and over a mean of 121 months (60-192 months) to assess radiographic and clinical responses.

RESULTS

The 90 patients included in our study cohort underwent a total of 108 stereotactic surgical procedures for 129 craniopharyngioma-related cysts. Of the included tumors, 65 (72.2%) were associated with a single cyst, 15 (16.7%) were associated with 2 cysts, and 10 (11.1%) tumors had developed septations with 3 to 4 cysts. Stereotactic cyst puncture and content aspiration were used to drain a mean cyst fluid volume of 21.4 mL (1.0-55.0 mL). Each cyst was then instilled for interstitial brachytherapy with colloidal P-32 solution. Based on radiographic follow-up assessments, 56 cysts (43.4%) showed resolution and/or nonrecurrence, which was classified as a complete response to treatment; 47 cysts (36.4%) showed a partial response; and 5 cysts (3.9%) displayed a stable appearance. Treatment resulted in immediate and clinically significant vision improvement in 54 of 63 (86%) symptomatic patients, and this improvement was maintained. Progression-free survival rates at 5 and 10 years were 95.5% and 84.4%, respectively.

CONCLUSIONS

P-32-based interstitial brachytherapy can play an effective role in managing patients with cystic craniopharyngiomas. It can be considered a valid alternative to surgery in select patients with a favorable toxicity profile and long-term clinical outcomes.

Adamantinomatous craniopharyngioma as a model to understand paracrine and senescence-induced tumourigenesis

Cellular senescence is a process that can prevent tumour development in a cell autonomous manner by imposing a stable cell cycle arrest after oncogene activation. Paradoxically, senescence can also promote tumour growth cell non-autonomously by creating a permissive tumour microenvironment that fuels tumour initiation, progression to malignancy and metastasis. In a pituitary tumour known as adamantinomatous craniopharyngioma (ACP), cells that carry oncogenic β-catenin mutations and overactivate the WNT signalling pathway form cell clusters that become senescent and activate a senescence-associated secretory phenotype (SASP). Research in mouse models of ACP has provided insights into the function of the senescent cell clusters and revealed a critical role for SASP-mediated activities in paracrine tumour initiation. In this review, we first discuss this research on ACP and subsequently explore the theme of paracrine tumourigenesis in other tumour models available in the literature. Evidence is accumulating supporting the notion that paracrine signalling brought about by senescent cells may underlie tumourigenesis across different tumours and cancer models.

Clinical features and prognosis of pediatric infradiaphragmatic craniopharyngioma relative to the tumor inflammatory response

BACKGROUND

The relationship between clinical responses in pediatric infradiaphragmatic craniopharyngioma (Q-CP) and inflammatory response is still unclear. The objective of this study was to investigate the clinical significance of tumor inflammatory response in pediatric Q-CPs.

METHODS

The inflammatory response was evaluated by measuring the number of inflammatory cells in the tumor near adenohypophysis junction. The specimens were classified as mild, moderate, or severe based on the number of inflammatory cells. In addition, the levels of pro-inflammatory cytokines and chemokines in the specimens were measured using a cytokine antibody array. Clinical outcomes were analyzed and compared to the markers of inflammatory response.

RESULTS

IL-6 and IL-8 were highly expressed in pediatric Q-CPs, and the transcription level of IL-6 was the highest in the severe group. Most patients (87.3%) had hypopituitarism; the severe inflammation group had an increased incidence of hypopituitarism, which correlated with significantly lower probability of recurrence-free survival and worsened functional status.

CONCLUSIONS

Inflammatory response is common in craniopharyngiomas and is closely related to their biological behavior and the patients' clinical prognosis. Further studies of the relationship between craniopharyngiomas and the inflammatory response will enable the discovery of potential therapeutic targets, which will reduce morbidity and result in better outcomes for pediatric Q-CP patients.

IMPACT

Pediatric infradiaphragmatic craniopharyngiomas are histologically benign brain tumors that often follow an aggressive clinical course. The inflammatory response in craniopharyngioma is common, which is closely related to the biological behavior and clinical prognosis. Several inflammatory and immune markers have been identified in CP; inflammation is an important role in the pathogenesis of hypopituitarism. The aim was to study the relationship between craniopharyngioma and inflammatory response and find potential therapeutic targets can reduce morbidity and result in better outcomes.

Identification of tumor stem-like cells in admanatimomatous craniopharyngioma and determination of these cells' pathological significance

OBJECTIVE

Nuclear β-catenin, a hallmark of active canonical Wnt signaling, can be histologically detected in a subset of cells and cell clusters in up to 94% of adamantinomatous craniopharyngioma (ACP) samples. However, it is unclear whether nuclear β-catenin-containing cells within human ACPs possess the characteristics of tumor stem cells, and it is unknown what role these cells have in ACP.

METHODS

Primary ACP cells were cultured from 12 human ACP samples. Adamantinomatous CP stem cell-like cells (CSLCs) showing CD44 positivity were isolated from the cultured primary ACP cells by performing magnetic-activated cell sorting. The tumor sphere formation, cell cycle distribution, stemness marker expression, and multidifferentiation potential of the CD44- cells and the CSLCs were analyzed.

RESULTS

Compared with the CD44- cells, the cultured human CSLCs formed tumor spheres and expressed CD44 and CD133; moreover, these cells demonstrated nuclear translocation of β-catenin. In addition, the CSLCs demonstrated osteogenic and adipogenic differentiation capacities compared with the CD44- cells. The CSLCs also displayed the capacity for tumor initiation in human-mouse xenografts.

CONCLUSIONS

These results indicate that CSLCs play an important role in ACP development, calcification, and cystic degeneration.

Surgical management of craniopharyngiomas in adult patients: a systematic review and consensus statement on behalf of the EANS skull base section

BACKGROUND AND OBJECTIVE

Craniopharyngiomas are locally aggressive neuroepithelial tumors infiltrating nearby critical neurovascular structures. The majority of published surgical series deal with childhood-onset craniopharyngiomas, while the optimal surgical management for adult-onset tumors remains unclear. The aim of this paper is to summarize the main principles defining the surgical strategy for the management of craniopharyngiomas in adult patients through an extensive systematic literature review in order to formulate a series of recommendations.

MATERIAL AND METHODS

The MEDLINE database was systematically reviewed (January 1970-February 2019) to identify pertinent articles dealing with the surgical management of adult-onset craniopharyngiomas. A summary of literature evidence was proposed after discussion within the EANS skull base section.

RESULTS

The EANS task force formulated 13 recommendations and 4 suggestions. Treatment of these patients should be performed in tertiary referral centers. The endonasal approach is presently recommended for midline craniopharyngiomas because of the improved GTR and superior endocrinological and visual outcomes. The rate of CSF leak has strongly diminished with the use of the multilayer reconstruction technique. Transcranial approaches are recommended for tumors presenting lateral extensions or purely intraventricular. Independent of the technique, a maximal but hypothalamic-sparing resection should be performed to limit the occurrence of postoperative hypothalamic syndromes and metabolic complications. Similar principles should also be applied for tumor recurrences. Radiotherapy or intracystic agents are alternative treatments when no further surgery is possible. A multidisciplinary long-term follow-up is necessary.

Adamantinomatous Craniopharyngioma in an Adult: A Case Report with NGS Analysis

PURPOSE

Several recent studies have documented CTNNB1 and BRAF mutations which are mutually exclusive for adamantinomatous craniopharyngioma (ACP) and papillary craniopharyngioma (PCP) tumors. This discovery is helpful in the development of novel targeted therapies in successful clinical trials with BRAF mutations in PCP cases. However, no such targeted therapy is available yet for ACP. Here, we report novel mutations, which are not previously reported, in a case of an adult ACP using NGS analysis.

RESULTS

Patient DNA was sequenced using Ion PI v3 chip on Ion Proton. A total of 16 variants were identified in this tumor by NGS analysis, out of which four were missense mutations, seven were synonymous mutations, and five were intronic variants. In CTNNB1 gene a known missense mutation in c.101G>T; in TP53 a known missense mutation in c.215C>G; and two known missense variants in PIK3CA, viz., in c.1173A>G; in exon 7, and in c.3128T>C; in exon 21, were found, respectively. Seven synonymous mutations were detected in this tumor, viz., in IDH1 (rs11554137), in FGFR3 (rs7688609), in PDGFRA (rs1873778), in APC (COSM3760869), in EGFR (rs1050171), in MET (rs35775721), and in RET (rs1800861), respectively. Three known, intronic variants were found in genes, such as PIK3CA, KDR, and JAK3, respectively. Also, a 3'-UTR and a splice site acceptor site variant in CSF1R and FLT3 genes were found in this tumor. We have shown allele coverage, allele ratio, and p-value, for all these mutations. The p-values and Phred quality score were significantly high for these variants.

CONCLUSION

As reported in previous studies, in ACP tumors we found a CTNNB1 mutation by NGS analysis. The PIK3CA variants we detected were not known previously in ACP tumors. Finding the PIK3CA mutations in the ACP tumors may help develop targeted therapy for a subset of craniopharyngiomas with PIK3CA activating mutations. Clinical trials are in progress with specific PIK3CA inhibitors in advanced stages of many cancers.

The Inflammatory Milieu of Adamantinomatous Craniopharyngioma and Its Implications for Treatment

Pediatric Adamantinomatous Craniopharyngiomas (ACPs) are histologically benign brain tumors that often follow an aggressive clinical course. Their suprasellar location leaves them in close proximity to critical neurological and vascular structures and often results in significant neuroendocrine morbidity. Current treatment paradigms, involving surgical resection and radiotherapy, confer significant morbidity to patients and there is an obvious need to discover effective and safe alternative treatments. Recent years have witnessed significant efforts to fully detail the genomic, transcriptomic and proteomic make-up of these tumors, in an attempt to identify potential therapeutic targets. These studies have resulted in ever mounting evidence that inflammatory processes and the immune response play a critical role in the pathogenesis of both the solid and cystic portion of ACPs. Several inflammatory and immune markers have been identified in both the cyst fluid and solid tumor tissue of ACP. Due to the existence of effective agents that target them, IL-6 and immune checkpoint inhibitors seem to present the most likely immediate candidates for clinical trials of targeted immune-related therapy in ACP. If effective, such agents may result in a paradigm shift in treatment that ultimately reduces morbidity and results in better outcomes for our patients.

The Medical Therapy of Craniopharyngiomas: The Way Ahead

CONTEXT

Craniopharyngiomas, which are categorized as adamantinomatous (ACPs) or papillary (PCPs), have traditionally been treated with surgery and/or radiotherapy, although when the tumors progress or recur, therapeutic possibilities are very limited. Following recent advances in their molecular pathogenesis, new medical therapeutic options have emerged.

EVIDENCE ACQUISITION

The search strategy that we selected to identify the appropriate evidence involved the following medical subject headings (MeSH) terms: ("Craniopharyngioma" [MeSH] AND "Craniopharyngioma/drug therapy" [MeSH]) NOT ("review" [Publication Type] OR "review literature as topic" [MeSH Terms] OR "review" [All Fields]) AND ("2009/05/01" [PDat]: "2019/04/28" [PDat]).

EVIDENCE SYNTHESIS

Mutations of β-catenin causing Wnt activation with alterations of the MEK/ERK pathway are encountered in the great majority of patients with ACPs; specific alterations also stratify patients to a more aggressive behavior. In most PCPs there is primary activation of the Ras/Raf/MEK/ERK pathway secondary to BRAF-V600E mutations. BRAF inhibitors, such as dabrafenib or vemurafenib, either alone or in combination with the MEK inhibitors trametinib and cobimetinib, have been administered to patients with PCPs producing clinically useful and, in some cases, sustained responses. In contrast to PCPs, drugs targeting β-catenin and its downstream MAPK pathway in ACPs have so far only been used in in vitro studies, but there appear to be promising new targets clinically.

CONCLUSIONS

The identification of specific genetic alterations in patients with craniopharyngiomas has expanded the therapeutic options, providing evidence for a customized approach using newer molecular agents. More studies including a larger number of carefully selected patients are required to evaluate the response to currently available and evolving agents alone and in combination.

Pediatric craniopharyngioma

BACKGROUND

Craniopharyngioma has historically been recognized to be a formidable pathology primarily due to its proximity to critical neurovascular structures and the challenging surgical corridors that surgeons have tried to reach this lesion.

FOCUS OF REVIEW

In this work, we review the medical and surgical management of these tumors with a focus on clinical presentation, diagnostic identification, surgical approach, and associated adjuvant therapies. We will also discuss our current treatment paradigm using endoscopic, open, and combined approaches to craniopharyngiomas. The management of craniopharyngiomas requires a multidisciplinary team of surgeons, endocrinologists, and neuroanesthesiologists as well as neurocritical care specialists to deliver the most comprehensive and safest surgical resection with minimal postoperative morbidity.

Craniopharyngiomas presenting as incidentalomas: results of KRANIOPHARYNGEOM 2007

PURPOSE

Childhood-onset craniopharyngiomas (CP) are diagnosed due to clinical symptoms (symCP) or incidentally (incCP). We investigated clinical manifestations and outcome in incCPs and symCPs.

METHODS

IncCP were discovered in 4 (3 m/1 f) and symCP in 214 (101 m/113 f) CP recruited 2007-2014 in KRANIOPHARYNGEOM 2007. Age, sex, height, body mass index (BMI), tumor volume, degree of resection, pre- and postsurgical hypothalamic involvement/lesions, pituitary function and outcome were compared between both subgroups.

RESULTS

Reasons for imaging in incCP were cerebral palsy, head trauma, nasal obstruction, and tethered-cord syndrome, whereas headache (44%), visual impairment (25%), and growth retardation (17%) lead to imaging in symCP. Tumor volume at diagnosis was smaller in incCP (median 2.39 cm³; range 0.14-4.10 cm³) when compared with symCP (15.86 cm³; 0.002-286.34 cm³). Age, gender, BMI, height, hydrocephalus, tumor location, and hypothalamic involvement at diagnosis of incCP were within the range of these parameters in symCP. Complete resections were achieved more frequently (3/4 patients) in incCP when compared with symCP (20%). Surgical hypothalamic lesions were distributed similar in incCP and symCP. Irradiation was performed only in symCP (33%). No noticeable differences were observed concerning survival rates, endocrine deficiencies, BMI, height, functional capacity and quality of life of the 4 incCP cases when compared with the symCP cohort.

CONCLUSIONS

IncCP are rare (1.8%) and characterized by lack of endocrine deficiencies, resulting in normal height and BMI, no hydrocephalus, and smaller tumor volume at diagnosis when compared with symCPs. Outcome of the observed incCP is similar with symCP.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01272622.

Investigating the Protein Signature of Adamantinomatous Craniopharyngioma Pediatric Brain Tumor Tissue: Towards the Comprehension of Its Aggressive Behavior

Although histologically benign, adamantinomatous craniopharyngioma (AC) pediatric brain tumor is a locally aggressive disease that frequently determines symptoms and hormonal dysfunctions related to the mass effect on the surrounding structures. Another typical feature of this benign neoplasm is the presence of voluminous liquid cysts frequently associated with the solid component. Even if studies have been devoted to the proteomic characterization of the tumor intracystic fluid, poor explorations have been performed on its solid part, principally investigated by transcriptomics technologies. In the present study, seven specimens of AC whole tumor tissue have been analyzed by LC-MS for a preliminary assessment of the proteomic profile by a top-down/bottom-up integrated approach. Thymosin beta 4, ubiquitin, calmodulin, S100 proteins, prothymosin α isoform 2, alpha-defensins 1-4, and fragments largely belonging to vimentin, hemoglobin, and glial fibrillary acidic protein characterized the intact proteome. The identification of alpha-defensins, formerly characterized in AC intracystic fluid, reinforces the hypothesis of a role for inflammation in tumor pathogenesis. A total number of 1798 unique elements were identified by a bottom-up approach with a special focus on the 433 proteins commonly characterized in the 85.7% of the samples analyzed. Their gene ontology classification evidenced the involvement of the adherence system, intermediate filaments, and actin cytoskeleton in tumor pathogenesis and of elements part of the Wnt, FGF, and EGFR signaling pathways. In addition, proteins involved in calcium modulation, innate immunity, inflammation, CCKR and integrin signaling, and gonadotropin-releasing hormone receptor pathways were also outlined. Further than confirming proteomic data previously obtained on AC intracystic fluid, these results offer a preliminary overview of the AC whole tissue protein phenotype, adding new hints towards the comprehension of this still obscure pediatric brain tumor.

Posterior hypothalamus-sparing surgery improves outcome after childhood craniopharyngioma

OBJECTIVE

Quality of life (QoL) is frequently impaired in childhood-onset craniopharyngioma (CP) by hypothalamic syndrome. The debate, whether pretreatment hypothalamic involvement (HI) has apriori prognostic impact or surgical hypothalamic lesions (HL) determine outcome, is controversial.

DESIGN

Survival and outcome of CPs recruited between 2007 and 2014 in KRANIOPHARYNGEOM 2007 were analyzed with regard to reference-confirmed presurgical HI and surgical HL.

METHODS

Radiological findings, BMI and QoL were assessed at diagnosis and during follow-up. QoL was assessed using Pediatric Quality of Life (PEDQOL) questionnaire.

RESULTS

One hundred sixty-nine CPs were included presenting with no HI (n = 11), anterior (n = 49) and anterior + posterior (a + p) HI (n = 109) prior to surgery. The latter 109 were analyzed for postoperative HL (no lesion: n = 23, anterior HL: n = 29, a + pHL: n = 57). Progression-free survival (PFS) was higher after complete resection. The highest PFS was observed in CP with a + pHL, especially when compared between non-irradiated subgroups (P = 0.006). Overall survival (OS) rates were 1.0 in all subgroups. CP with a + pHL developed higher BMI (P ≤ 0.001) during follow-up compared between subgroups. 55/109 pts with a + pHI completed PEDQOL at diagnosis (48/109 at 3 years follow-up). QoL was worse for a + pHL patients in terms of physical, social and emotional functionality when compared with the anterior HL and no HL subgroup. BMI development and QoL during follow-up were similar for patients with anterior HL and without HL.

CONCLUSIONS

Posterior hypothalamus-sparing surgical strategies are associated with higher QoL, decreased development of obesity and lower PFS in CP.

MANAGEMENT OF ENDOCRINE DISEASE: Childhood-onset craniopharyngioma: state of the art of care in 2018

This review presents an update on current concepts of pathogenesis, diagnostics, multidisciplinary treatment and follow-up care, with special focus on neuropsychological sequelae of childhood-onset craniopharyngioma (CP) based on most recent publications on these topics. Recent insight in molecular pathogenesis of CP opens new perspectives on targeted therapy. Further research to elucidate pathogenic mechanisms and to prevent hypothalamic involvement of CP is warranted. Surgical treatment strategies should be based on a multidisciplinary approach involving experienced teams aiming at posterior hypothalamus-sparing treatment for prevention of quality of life impairments. Centralization of CP treatment in experienced 'centers of excellence' is recommended. However, such centralization includes high thresholds concerning infrastructure not achievable in all health systems. Alternatives such as multicenter-based networks used for reference assessments should be considered to assure high standards of treatment quality. Irradiation is efficient in preventing further growth or recurrence in CP patients with residual tumor. Proton beam therapy - available on a wider range in the near future - will help to avoid radiooncological side effects. Novel insights into neuropsychological sequelae after CP should be the basis for the development of future therapeutic neuropsychological interventions. Due to the rareness of the disease, common international efforts in research and treatment are recommended and should lead to an international registry for childhood-onset CP, as a first step toward efficient coordination of scientific and clinical initiatives.

Comparison of neuroendocrine dysfunction in patients with adamantinomatous and papillary craniopharyngiomas

Craniopharyngiomas (CPs) are rare epithelial tumors mainly located in the sellar/parasellar region. They may be classified into two major histological subtypes, which exhibit clinical and pathological differences: Adamantinomatous CP (ACP) and papillary CP (PCP). The aim of the present study was to compare the neuroendocrine dysfunction between ACP and PCP prior to and after surgical resection. According to their pathological classification, the patients were assigned to the ACP group or the PCP group. The neuroendocrine dysfunction in these two CP subtypes was evaluated using a scoring method prior to and after surgery. A total of 741 patients with CPs were included in the present study, of which 622 were ACP and 119 were PCP. The scores on the tumor mass effect, hypothalamic dysfunction and pituitary-target gland axis dysfunction, as well as the incidence of central diabetes insipidus in the PCP group were all significantly higher than those in the ACP group, regardless of whether the surgery had been performed or not (all P<0.05). After surgery, the scores on the tumor mass effect were significantly decreased in the ACP and PCP patients (all P<0.05), while the scores on hypothalamic dysfunction and pituitary-target gland axis dysfunction, as well as the incidence of central diabetes insipidus were all significantly increased in ACP and PCP patients (all P<0.05). Prior to and after surgery, the PCP variant exhibited a greater damage to the neuroendocrine function compared with the ACP variant.

Regulation of Pituitary Progenitor Differentiation by β-Catenin

The pituitary gland is a critical organ that is necessary for many physiological processes, including growth, reproduction, and stress response. The secretion of pituitary hormones from specific cell types regulates these essential processes. Pituitary hormone cell types arise from a common pool of pituitary progenitors, and mutations that disrupt the formation and differentiation of pituitary progenitors result in hypopituitarism. Canonical WNT signaling through CTNNB1 (β-catenin) is known to regulate the formation of the POU1F1 lineage of pituitary cell types. When β-catenin is deleted during the initial formation of the pituitary progenitors, Pou1f1 is not transcribed, which leads to the loss of the POU1F1 lineage. However, when β-catenin is deleted after lineage specification, there is no observable effect. Similarly, the generation of a β-catenin gain-of-function allele in early pituitary progenitors or stem cells results in the formation of craniopharyngiomas, whereas stimulating β-catenin in differentiated cell types has no effect. PROP1 is a pituitary-specific transcription factor, and the peak of PROP1 expression coincides with a critical time point in pituitary organogenesis-that is, after pituitary progenitor formation but before lineage specification. We used a Prop1-cre to conduct both loss- and gain-of-function studies on β-catenin during this critical time point. Our results demonstrate that pituitary progenitors remain sensitive to both loss and gain of β-catenin at this time point, and that either manipulation results in hypopituitarism.

Precision Medicine for Primary Central Nervous System Tumors: Are We There Yet?

In recent years, technologic advances have increased tremendously our understanding of the molecular characteristics and genetic drivers of a variety of brain tumors. These discoveries have led to paradigm shifts in the treatment of these tumor entities and may therefore have a considerable impact on the outcome of affected patients in the near future. Here, we provide a broad overview of recently discovered clinically actionable mutations that have been identified in three different primary brain tumors: gliomas, meningiomas, and craniopharyngiomas. We furthermore highlight the diagnostic and therapeutic implications of these findings and summarize recently published and ongoing trials.

Tumour compartment transcriptomics demonstrates the activation of inflammatory and odontogenic programmes in human adamantinomatous craniopharyngioma and identifies the MAPK/ERK pathway as a novel therapeutic target

Adamantinomatous craniopharyngiomas (ACPs) are clinically challenging tumours, the majority of which have activating mutations in CTNNB1. They are histologically complex, showing cystic and solid components, the latter comprised of different morphological cell types (e.g. β-catenin-accumulating cluster cells and palisading epithelium), surrounded by a florid glial reaction with immune cells. Here, we have carried out RNA sequencing on 18 ACP samples and integrated these data with an existing ACP transcriptomic dataset. No studies so far have examined the patterns of gene expression within the different cellular compartments of the tumour. To achieve this goal, we have combined laser capture microdissection with computational analyses to reveal groups of genes that are associated with either epithelial tumour cells (clusters and palisading epithelium), glial tissue or immune infiltrate. We use these human ACP molecular signatures and RNA-Seq data from two ACP mouse models to reveal that cell clusters are molecularly analogous to the enamel knot, a critical signalling centre controlling normal tooth morphogenesis. Supporting this finding, we show that human cluster cells express high levels of several members of the FGF, TGFB and BMP families of secreted factors, which signal to neighbouring cells as evidenced by immunostaining against the phosphorylated proteins pERK1/2, pSMAD3 and pSMAD1/5/9 in both human and mouse ACP. We reveal that inhibiting the MAPK/ERK pathway with trametinib, a clinically approved MEK inhibitor, results in reduced proliferation and increased apoptosis in explant cultures of human and mouse ACP. Finally, we analyse a prominent molecular signature in the glial reactive tissue to characterise the inflammatory microenvironment and uncover the activation of inflammasomes in human ACP. We validate these results by immunostaining against immune cell markers, cytokine ELISA and proteome analysis in both solid tumour and cystic fluid from ACP patients. Our data support a new molecular paradigm for understanding ACP tumorigenesis as an aberrant mimic of natural tooth development and opens new therapeutic opportunities by revealing the activation of the MAPK/ERK and inflammasome pathways in human ACP.

Stem/progenitor cells in pituitary organ homeostasis and tumourigenesis

Evidence for the presence of pituitary gland stem cells has been provided over the last decade using a combination of approaches including in vitro clonogenicity assays, flow cytometric side population analysis, immunohistochemical analysis and genetic approaches. These cells have been demonstrated to be able to self-renew and undergo multipotent differentiation to give rise to all hormonal lineages of the anterior pituitary. Furthermore, evidence exists for their contribution to regeneration of the organ and plastic responses to changing physiological demand. Recently, stem-like cells have been isolated from pituitary neoplasms raising the possibility that a cytological hierarchy exists, in keeping with the cancer stem cell paradigm. In this manuscript, we review the evidence for the existence of pituitary stem cells, their role in maintaining organ homeostasis and the regulation of their differentiation. Furthermore, we explore the emerging concept of stem cells in pituitary tumours and their potential roles in these diseases.

High-resolution melting and immunohistochemical analysis efficiently detects mutually exclusive genetic alterations of adamantinomatous and papillary craniopharyngiomas

Craniopharyngioma consists of adamantinomatous and papillary subtypes. Recent genetic analysis has demonstrated that the two subtypes are different, not only in clinicopathological features, but also in molecular oncogenesis. Papillary craniopharyngioma (pCP) is characterized by a BRAF mutation, the V600E (Val 600 Glu) mutation. Adamantinomatous craniopharyngioma (aCP) can be distinguished by frequent β-catenin gene (CTNNB1) mutations. Although these genetic alterations can be a diagnostic molecular marker, the precise frequency of these mutations in clinical specimens remains unknown. In this study, we first evaluated BRAF V600E and CTNNB1 mutations in four and 14 cases of pCP and aCP, respectively, using high-resolution melting analysis followed by Sanger sequencing. The results showed that 100% (4/4) of pCP cases had BRAF V600E mutations, while 78% (11/14) of the aCP cases had CTNNB1 mutations, with these genetic alterations being subtype-specific and mutually exclusive. Second, we evaluated BRAF V600E and CTNNB1 mutations by immunohistochemical analysis (IHC). All pCP cases showed positive cytoplasmic staining with the BRAF V600E-mutant antibody (VE-1), whereas 86% (12/14) of aCP cases showed positive cytoplasmic and nuclear staining for CTNNB1, suggesting a CTNNB1 mutation. Only one case of wild-type CTNNB1 on the DNA analysis showed immunopositivity on IHC. We did not detect a coexistence of BRAF V600E and CTNNB1 mutations in any single tumor, which indicated that these genetic alterations were mutually exclusive. We also report our modified IHC protocol for VE-1 staining, and present the possibility that BRAF V600E mutations can be used as a diagnostic marker of pCP in the differentiation of Rathke cleft cyst with squamous metaplasia.

Recent advances in molecular pathology of craniopharyngioma

Craniopharyngiomas are rare epithelial tumours arising along the path of the craniopharyngeal duct. Two major histological subtypes have been recognised, the papillary and the adamantinomatous. Craniopharyngiomas remain challenging tumours to manage and are associated with significant morbidities and mortality. Recent advances in the molecular pathology of these neoplasms have identified BRAF mutations in the papillary variant, offering promising options for targeted pharmacological treatment. The involvement of β-catenin and the Wnt pathway in the tumorigenesis of the adamantinomatous subtype has been previously established with the identification of stabilising mutations in exon 3 of CTNNB1. Further understanding of the pathogenesis of this subtype has been facilitated with the use of mouse models and xenograft experiments. It has been proposed that the clusters of cells with upregulated Wnt/β-catenin signalling induce tumour formation in a paracrine manner; the complex interactions occurring between different cell populations need to be further clarified for further expansion of this hypothesis. This review outlines recent key advances in our understanding of the molecular pathology of craniopharyngiomas and discusses some of the challenges that need to be overcome for the development of targeted therapies that will hopefully improve the management and the outcomes of these patients.

Can recurrences be predicted in craniopharyngiomas? β-catenin coexisting with stem cells markers and p-ATM in a clinicopathologic study of 45cases

Background

Recurrence is a common feature of craniopharyngiomas, benign tumors that origin from squamous epithelial remnants of Rathke’s pouch- arising at any segment of its whole course. There are two histotypes, showing different morphology and clinical behavior: adamantinomatous(adaCP) and papillary (papCP). An univocal strategy of management has not yet been defined, being considered the combination of surgery and radiotherapy the most effective, especially in case of incomplete resection. Therefore, the identification of factors influencing the biological and clinical behaviour is of paramount importance.

β-catenin is a cell-cell adhesion protein, whose nuclear localization has been linked to the pathogenesis of adaCP: its nuclear accumulation is associated to the presence of a tumor stem cell subpopulation. The latter is made of cells capable of self-renewal, hence believed to be responsible of recurrence, metastases and resistance to therapy in all tumors.

ATM is a kinase activated by autophosphorylation (p-ATM) upon DNA double-strand breaks. It is involved not only in DNA repair, but also in tumor migration and invasiveness. Its expression may have prognostic implications in many neoplastic diseases.

Methods

In this study, we measured the immunohistochemical expression of β-catenin, stem cell markers (CD133, CD166), Ki67 and pATMin 45 craniopharyngiomas and correlated it with clinicopathologic features.

Results

Statistical analysis revealed strong correlation of β-catenin with recurrence (p = 0.0039), Ki67 (p = 0.0011, r = 0.4903) and CD166 (p = 0.0002, r = 0.6218). A slight tendency to a higher expression of β-catenin was recorded for adaCP rather than papCP (p = 0.0895).Fisher’s exact test showed that CD166 was significantlyrelated with recurrence (p = 0.0040). Furthermore, cytoplasmic pATM was more expressed in adaCPs (p = 0.0470), compared to papCPs that displayed a more evident nuclear signal (p = 0.0313) instead.

Conclusions

Backing upon these data, we could weigh in on the need of identifying β-catenin and CD166 as prognostic markersthat could be useful in predicting thebiologicalbehavior, as recurrence risk incraniopharyngiomas. The final goal is to drew up a prognostic algorithm to be of aid in the planning of an appropriate treatment strategy. Furthermore, our findings demonstrate that pATM could be used as additional distinction-marker between the two histotypes.

Genomic Alterations of Adamantinomatous and Papillary Craniopharyngioma

Craniopharyngiomas are rare histologically benign but clinically challenging neoplasms. To obtain further information on the molecular genetics and biology of craniopharyngiomas, we analyzed a cohort of 121 adamantinomatous and 16 papillary craniopharyngiomas (ACP, PCP). We extracted DNA from formalin-fixed paraffin-embedded tissue and determined mutational status of CTNNB1, BRAF, and DDX3X by Sanger sequencing, next generation panel sequencing, and pyrosequencing. Sixteen craniopharyngiomas were further analyzed by molecular inversion profiling (MIP); 76.1% of the ACP were mutated in exon 3 of CTNNB1 encoding for β-catenin and there was a trend towards a worse event-free survival in cases mutated at Thr41. Next generation panel sequencing of 26 ACP did not detect any recurrent mutations other than CTNNB1 mutations. BRAF V600E mutations were found in 94% of the PCP, but not in ACP. GISTIC analysis of MIP data showed no significant larger chromosomal aberrations but a fraction of ACP showed recurrent focal gains of chromosomal material, other cases showed loss in the chromosomal region Xq28, and a third group and the PCP had stable genomes. In conclusion, the crucial pathogenetic event appears to be WNT activation in ACP, whereas it appears to be activation of the Ras/Raf/MEK/ERK pathway by BRAF V600E mutations in PCP.

Diagnosis and management of craniopharyngiomas in the era of genomics and targeted therapy

Craniopharyngiomas are rare intracranial neoplasms that pose clinical challenges due to their location adjacent to vital structures. The authors have previously shown high mutation rates of BRAF V600E in papillary craniopharyngioma and of CTNNB1 in adamantinomatous craniopharyngioma. These activating driver mutations are potential therapeutic targets, and the authors have recently reported a significant response to BRAF/MEK inhibition in a patient with multiply recurrent PCP. As these targetable mutations warrant prospective research, the authors will be conducting a national National Cancer Institute-sponsored multicenter clinical trial to investigate BRAF/MEK inhibition in the treatment of craniopharyngioma. In this new era of genomic discovery, the treatment paradigm of craniopharyngioma is likely to change.

EpCAM (CD326) is differentially expressed in craniopharyngioma subtypes and Rathke's cleft cysts

The epithelial cell adhesion molecule (EpCAM) is a type I glycoprotein located on the surface of epithelial cells. It is strongly expressed in many neoplasms and already used in the diagnosis and distinction of various tumour subtypes. Comparative studies about EpCAM expression in cystic sellar lesions are lacking. Therefore, we analysed its distribution pattern in adamantinomatous (aCP) and papillary (pCP) craniopharyngiomas (CP) and Rathke’s Cleft Cysts (RCC) using immunohistochemistry and gene expression profiling. Whereas the protein was not detectable in pCP (n = 10), all aCP (n = 64) showed distinct staining patterns. The vast majority of RCC (n = 10) also appeared positive, but these displayed notably lower labeling scores. Additionally, significantly higher mRNA levels were detectable in aCP (n = 19) when compared to pCP (n = 10) (p = 9.985⁻⁸). Furthermore, pediatric aCP cases, in general, exhibited stronger EpCAM staining levels compared to adult ones (p = 0.015). However, we were not able to verify this result on mRNA level. In summary, our findings demonstrate that EpCAM can be used as an additional distinction-marker for cystic lesions of the sellar region. Its unknown function in aCP and the presence of an approved monoclonal bispecific trifunctional antibody for cancer therapy are interesting starting points for further studies.

ENDOCRINE TUMORS: BRAF V600E mutations in papillary craniopharyngioma

Papillary craniopharyngioma (PCP) is an intracranial tumor that results in high levels of morbidity. We recently demonstrated that the vast majority of these tumors harbor the oncogenic BRAF V600E mutation. The pathologic diagnosis of PCP can now be confirmed using mutation specific immunohistochemistry and targeted genetic testing. Treatment with targeted agents is now also a possibility in select situations. We recently reported a patient with a multiply recurrent PCP in whom targeting both BRAF and MEK resulted in a dramatic therapeutic response with a marked anti-tumor immune response. This work shows that activation of the MAPK pathway is the likely principal oncogenic driver of these tumors. We will now investigate the efficacy of this approach in a multicenter phase II clinical trial. Post-treatment resection samples will be monitored for the emergence of resistance mechanisms. Further advances in the non-invasive diagnosis of PCP by radiologic criteria and by cell-free DNA testing could someday allow neo-adjuvant therapy for this disease in select patient populations.

Craniopharyngioma and hypothalamic injury: latest insights into consequent eating disorders and obesity

PURPOSE OF REVIEW

Hypothalamic alterations, pathological or treatment induced, have major impact on prognosis in craniopharyngioma patients mainly because of consequent hypothalamic obesity. Recent insight in molecular genetics, treatment strategies, risk factors and outcomes associated with hypothalamic obesity provide novel therapeutic perspectives. This review includes relevant publications since 2013.

RECENT FINDINGS

Recent findings confirm that alterations in posterior hypothalamic areas because of tumour location and/or treatment-related injuries are associated with severe hypothalamic obesity, reduced overall survival and impaired quality of life in long-term survivors of childhood-onset craniopharyngioma. However, eating disorders are observed because of hypothalamic obesity without clear disease-specific patterns. Treatment options for hypothalamic obesity are very limited. Treatment with invasive, nonreversible bariatric methods such as Roux-en-Y gastric bypass is most efficient in weight reduction, but controversial in the paediatric population because of medical, ethical, and legal considerations. Accordingly, treatment in craniopharyngioma should focus on prevention of (further) hypothalamic injury. Presurgical imaging for grading of hypothalamic involvement should be the basis for hypothalamus-sparing strategies conducted by experienced multidisciplinary teams.

SUMMARY

Until a nonsurgical therapeutic option for hypothalamic obesity for paediatric patients is found, prevention of hypothalamic injury should be the preferred treatment strategy, conducted exclusively by experienced multidisciplinary teams.

Concise Review: Paracrine Role of Stem Cells in Pituitary Tumors: A Focus on Adamantinomatous Craniopharyngioma

The existence of tissue‐specific progenitor/stem cells in the adult pituitary gland of the mouse has been demonstrated recently using genetic tracing experiments. These cells have the capacity to differentiate into all of the different cell lineages of the anterior pituitary and self‐propagate in vitro and can therefore contribute to normal homeostasis of the gland. In addition, they play a critical role in tumor formation, specifically in the etiology of human adamantinomatous craniopharyngioma, a clinically relevant tumor that is associated with mutations in CTNNB1 (gene encoding β‐catenin). Mouse studies have shown that only pituitary embryonic precursors or adult stem cells are able to generate tumors when targeted with oncogenic β‐catenin, suggesting that the cell context is critical for mutant β‐catenin to exert its oncogenic effect. Surprisingly, the bulk of the tumor cells are not derived from the mutant progenitor/stem cells, suggesting that tumors are induced in a paracrine manner. Therefore, the cell sustaining the mutation in β‐catenin and the cell‐of‐origin of the tumors are different. In this review, we will discuss the in vitro and in vivo evidence demonstrating the presence of stem cells in the adult pituitary and analyze the evidence showing a potential role of these stem cells in pituitary tumors. Stem Cells2016;34:268–276

60 YEARS OF NEUROENDOCRINOLOGY: Biology of human craniopharyngioma: lessons from mouse models

Adamantinomatous craniopharyngiomas (ACP) are clinically relevant tumours that are associated with high morbidity, poor quality of life and occasional mortality. Human and mouse studies have provided important insights into the biology of these aggressive tumours, and we are starting to understand why, how and when these tumours develop in humans. Mutations in β-catenin that result in the over-activation of the WNT/β-catenin signalling pathway are critical drivers of most, perhaps of all, human ACPs. Mouse studies have shown that only pituitary embryonic precursors or adult stem cells are able to generate tumours when targeted with oncogenic β-catenin, which suggests that the cell context is critical in order for mutant β-catenin to exert its oncogenic effect. Interestingly, mutant stem cells do not generate the bulk of the tumour cells; instead, they induce tumours in a paracrine manner. Combining basic studies in mice and humans will provide further insights into the biology of these neoplasms and will reveal pathogenic pathways that could be targeted with specific inhibitors for the benefit of patients. These benign tumours may additionally represent a unique model for investigating the early steps that lead to oncogenesis.

Identification of targets for rational pharmacological therapy in childhood craniopharyngioma

Introduction

Pediatric adamantinomatous craniopharyngioma (ACP) is a histologically benign but clinically aggressive brain tumor that arises from the sellar/suprasellar region. Despite a high survival rate with current surgical and radiation therapy (75–95 % at 10 years), ACP is associated with debilitating visual, endocrine, neurocognitive and psychological morbidity, resulting in excheptionally poor quality of life for survivors. Identification of an effective pharmacological therapy could drastically decrease morbidity and improve long term outcomes for children with ACP.

Results

Using mRNA microarray gene expression analysis of 15 ACP patient samples, we have found several pharmaceutical targets that are significantly and consistently overexpressed in our panel of ACP relative to other pediatric brain tumors, pituitary tumors, normal pituitary and normal brain tissue. Among the most highly expressed are several targets of the kinase inhibitor dasatinib – LCK, EPHA2 and SRC; EGFR pathway targets – AREG, EGFR and ERBB3; and other potentially actionable cancer targets – SHH, MMP9 and MMP12. We confirm by western blot that a subset of these targets is highly expressed in ACP primary tumor samples.

Conclusions

We report here the first published transcriptome for ACP and the identification of targets for rational therapy. Experimental drugs targeting each of these gene products are currently being tested clinically and pre-clinically for the treatment of other tumor types. This study provides a rationale for further pre-clinical and clinical studies of novel pharmacological treatments for ACP. Development of mouse and cell culture models for ACP will further enable the translation of these targets from the lab to the clinic, potentially ushering in a new era in the treatment of ACP.