Intronic mutation of the VHL gene associated with central nervous system hemangioblastomas in two Chinese families with Von Hippel-Lindau disease: case report.

BACKGROUND: Central nervous system (CNS) hemangioblastomas are the most frequent cause of mortality in patients with Von Hippel-Lindau (VHL) disease, an autosomal dominant genetic disease resulting from germline mutations in the VHL tumor suppressor gene, with most mutations occurring in the exons. To date, there have been no reports of CNS hemangioblastoma cases related to pathogenic variants in intron 2 of VHL, which encodes a tumor suppressor protein (i.e., pVHL) that regulates hypoxia-inducible factor proteins. CASE PRESENTATION: We report the presence of a base substitution of c.464-1G > C and c.464-2A > G in the intron 2 of VHL causing CNS hemangioblastomas in six patients with VHL from two Chinese families. The clinical information about the two pathogentic variants has been submitted to ClinVar database. The ClinVar accession for NM_000551.3(VHL):c.464-1G > C was SCV001371687. This finding may provide a new approach for diagnosing and researching VHL-associated hemangioblastomas. CONCLUSIONS: This is the first report of a pathogenic variant at intron 2 in VHL-associated hemangioblastomas. Gene sequencing showed that not only exonic but also intronic mutations can lead to the development of CNS hemangioblastomas.

Biological and clinical impact of central nervous system hemangioblastomas in Chinese patients with von Hippel-Lindau disease: implications for treatment.

OBJECTIVE: Central nervous system (CNS) hemangioblastomas (HGBs) are the most frequent cause of mortality in patients with von Hippel-Lindau (VHL) genetic syndrome. However, there is a lack of large studies on the clinical features and optimal management of HGBs in Chinese patients. METHODS: VHL-related HGB cases treated surgically at our hospital from 2012 to 2019 were evaluated. Patients and family members meeting the clinical diagnostic criteria underwent genetic testing. Clinical, genetic and relevant imaging data were analyzed. RESULTS: Eighty-five VHL patients from 34 pedigrees in 16 Chinese provinces who underwent 121 operations for CNS HGBs were enrolled. Multiple operations were associated with a younger age at first operation (OR = 0.926, 95% CI = 0.871-0.985, P = 0.014, threshold: 27.5, sensitivity: 72.2%, specificity: 71.2%) and a longer postoperative period (OR = 1.096, 95% CI = 1.015-1.184, P = 0.019, threshold: 10.5, sensitivity: 66.7%, specificity: 76.3%). The age at first operation was younger in children than in their parents (23 pairs, P < 0.001). The age at first operation was younger in siblings born later than in those born earlier (10 pairs, P = 0.01). Most untreated tumors (98.2%) remained relatively stable during follow-up (range, 0.5-7; median, 2). However, new tumors continued to emerge (0.14 tumor/year). CONCLUSION: VHL-associated CNS HGB is a long-term chronic disease with repeated attacks, likely with genetic anticipation in Chinese pedigrees. When the age at first operation is under 27.5 years, or the postoperative period is longer than 10.5 years, the risk of multiple operations is increased. While most unresected HGBs remain stable after surgery, new tumors may still slowly emerge; hence, scheduled follow-ups are necessary.

Effects of the estrogen receptor antagonist fulvestrant on F344 rat prolactinoma models.

The relationship between estrogen and prolactinoma is well documented. But the anti-tumor effects of a pure estrogen receptor antagonist fulvestrant on prolactinomas, especially in vivo, and the possible mechanisms are still unclear. Therefore, the aim of this study was to evaluate the effects of fulvestrant and the involvement of the Wnt signaling pathway on rat prolactinoma models. Forty female F344 rat prolactinoma models were established by subcutaneous administration of 10 mg 17ß-estradiol for 6 weeks. Rats were intramuscularly injected with fulvestrant (0, 0.5, 3, 20, 40 mg/kg), and tumor size, weight and serum prolactin (PRL) levels were evaluated before and after fulvestrant treatment at 3, 7 and 14 days. Expression of estrogen receptor α (ERα), ß-catenin and Wnt inhibitory factor-1 (WIF-1) in prolactinomas was measured using quantitative PCR and western blotting, and methylation of the WIF-1 promoter was investigated using pyrosequencing. Tumor size, weight and serum PRL levels were inhibited in dose-dependent and time-dependent manners after fulvestrant treatments. ß-catenin expression was downregulated but WIF-1 expression was upregulated following fulvestrant treatment. The methylation of the CpG site of the WIF-1 promoter was negatively correlated to the expression of WIF-1. In addition, the anti-cell proliferation of fulvestrant on GH3 cells was partly disrupted by Wnt signaling pathway agonist SB 216763. In conclusion, fulvestrant inhibited tumor proliferation and PRL secretion of prolactinomas via ERα, and the Wnt signaling pathway was involved in this anti-tumor effect. Therefore, fulvestrant may be a potential new drug for prolactinomas.

Low levels of PRB3 mRNA are associated with dopamine-agonist resistance and tumor recurrence in prolactinomas.

Prolactinomas, or prolactin-secreting adenomas, constitute the most common type of hyperfunctioning pituitary adenoma. Dopamine agonists are used as first-line medication for prolactinomas, but the tumors are resistant to the therapy in 5-18 % of patients. To explore potential mechanisms of resistance to bromocriptine (a dopamine agonist), we analyzed six responsive prolactinomas and six resistant prolactinomas by whole-exome sequencing. We identified ten genes with sequence variants that were differentially found in the two groups of tumors. The expression of these genes was then quantified by real-time reverse-transcription PCR (RT-qPCR) in the 12 prolactinomas and in six normal pituitary glands. The mRNA levels of one of the genes, PRB3, were about fourfold lower in resistant prolactinomas than in the responsive tumors (p = 0.02). Furthermore, low PRB3 expression was also associated with tumor recurrence. Our results suggest that low levels of PRB3 mRNA may have a role in dopamine-agonist resistance and tumor recurrence of prolactinomas.

Expression of pituitary tumor transforming gene (PTTG) in human pituitary macroadenomas.

The purpose of this study was to elucidate the relationship between pituitary tumor transforming gene (PTTG) and invasiveness in pituitary macroadenomas and to determine the association between PTTG and both the tumor proliferative activity marker proliferation cell nuclear antigen (PCNA) and the angiogenic factor basic fibroblast growth factor. A total of 70 patients with pituitary adenomas who underwent transsphenoidal or craniotomy surgical resection were enrolled. The average age were 42.5 ± 13.7 years (17-64 years) for the invasive group and 46.8 ± 12.1 years (16-71 years) for the non-invasive group, with no significant difference (P=0.179) between the two groups. RT-PCR analysis of a group of pituitary macroadenomas demonstrated that the expression levels of PTTG and PCNA in invasive pituitary adenomas were significantly higher than in non-invasive pituitary adenomas. Both factors are both closely related to the invasive growth of pituitary adenomas and may possibly serve as important markers of this growth. In conclusion, PTTG may promote invasive tumor growth by stimulating pituitary adenomas proliferation. The mechanisms of tumor growth promotion and invasion of the surrounding structures by PTTG need to be further explored.

Clinical Characteristics, Surgical Treatment, and Risk Factor Analysis of Postoperative Functional Outcome in Patients with Intracranial Hemangioblastoma.

OBJECTIVE: This study aims to present the clinical characteristics and surgical treatment in patients with intracranial hemangioblastomas and to investigate risk factors for postoperative functional outcomes. METHODS: Patients with intracranial hemangioblastomas who received surgical treatment in our institute between 2011 and 2020 were included. We retrospectively reviewed and analyzed the clinical characteristics, surgical treatment, and postoperative functional status. Risk factors for postoperative functional outcomes were further analyzed using univariate and multivariate analysis. RESULTS: We identified 48 patients with 82 intracranial hemangioblastomas resected in this study. There were 22 females and 26 males, and the mean age was 39.3 ± 15.3 years. Total resection was achieved in all the cases. After primary surgery, immediate functional status was improved in 20 patients (41.7%), stable in 9 patients (18.8%), and worsened in 19 patients (39.6%). Forty-two patients (89.4%) had favorable functional status (Karnofsky Performance Scale ≥80) at long-term follow-up. Through univariate and multivariate analysis, body mass index, number of resected tumors per operation, and intraoperative blood loss were independent risk factors for the immediate functional outcome (P = 0.006, P = 0.023, P = 0.038, respectively). Preoperative hydrocephalus was significantly associated with unfavorable long-term functional status (P = 0.047). CONCLUSIONS: Generally, patients can benefit from surgical removal of intracranial hemangioblastomas with favorable functional outcomes. Body mass index, number of resected tumors per operation, and intraoperative blood loss can be used as risk factors for immediate functional outcomes after surgery, and preoperative hydrocephalus for long-term functional status.

Incidence, Prognostic Factors and Survival for Hemangioblastoma of the Central Nervous System: Analysis Based on the Surveillance, Epidemiology, and End Results Database.

BACKGROUND: Hemangioblastomas are uncommon, benign neoplasms of the central nervous system (CNS). This study aims to evaluate the incidence, demographics, clinical characteristics, and prognosis of CNS hemangioblastomas using the data from the Surveillance, Epidemiology, and End Results (SEER) Program. METHODS: Univariate and multivariate analyses using the Cox proportional hazards model were employed to identify prognostic factors of overall survival. The Kaplan-Meier method was utilized to evaluate overall survival distribution by treatment modality. A nomogram was further built to predict survival at 3 and 5 years. RESULTS: The overall incidence rate of CNS hemangioblastomas was 0.141 per 100,000 person-years. Through univariate analysis and multivariate analyses, age between 60 and 79 years (HR = 3.697, p < 0.001), age greater than 80 years (HR = 12.318, p < 0.001), African American race (HR = 1.857, p = 0.003), multiple tumors (HR = 1.715, p < 0.001), and prior surgery (HR = 0.638, p = 0.013) were significantly associated with overall survival. Patients receiving surgery alone had better overall survival compared with patients receiving no treatment (p = 0.008) and patients receiving both surgery and radiotherapy (p = 0.002). The calibration plots demonstrated an excellent agreement between nomogram-predicted and actual survival. CONCLUSION: In conclusion, age, race, tumor location, number of tumors, and prior surgery are prognostic factors for survival. Surgery was the most common modality and was suggested as an effective and optimal treatment. The proposed nomogram can predict the prognosis of patients with CNS hemangioblastomas and help clinicians in making decisions.

Overexpression of EGFR and TGFα in von Hippel-Lindau-Related Central Nervous System Hemangioblastomas.

Background: Central nervous system (CNS) hemangioblastomas (HGBs) are the most frequent cause of mortality in patients with von Hippel-Lindau (VHL) disease. Characteristics of multiple and recurrent disease cause certain difficulties in the treatment of CNS HGBs. Methods: VHL-related HGB cases treated surgically at our hospital from September 2015 to February 2019 were analyzed. Patients meeting the clinical diagnostic criteria underwent genetic testing. Real-time PCR and immunohistochemistry were used in HGBs to verify differential expression of mRNAs and proteins, respectively. Furthermore, correlations between the differentially expressed proteins and the histological grading, genetic mutations, and tumor burden were also analyzed. Results: A total of 21 patients with VHL syndrome confirmed by genetic testing (missense group, 9; partial deletion group, 12) were enrolled, and 30 CNS HGBs from these patients were studied. Clinical data showed that men at first operation were significantly younger than females (p = 0.005). Real-time PCR demonstrated that EGFR (p = 0.017) and TGFα (p = 0.017) mRNA expression in VHL-related HGBs was significantly higher than that in the control group. Immunohistochemistry showed that the mean optical density in VHL-related HGBs was significantly higher than that in controls (EGFR, p = 0.007; TGFα, p = 0.021). Finally, the cyst volume was related to the upregulation of EGFR (r = 0.782, p < 0.01). Conclusion: Overexpression of EGFR and TGFα may contribute to tumor growth in VHL-related CNS HGBs. The cyst volume was associated with EGFR overexpression. These results provide information for the management of VHL-related HGBs in the era of targeted therapeutics.

Endoscopic Treatment of an Adult with Tegmental Astrocytoma Accompanied by Cerebrospinal Fluid Dissemination.

Midbrain gliomas are relatively rare neoplasms with a generally benign prognosis, with dissemination or metastasis not previously reported. We describe here a woman, in whom magnetic resonance imaging scans showed hydrocephalus and a tegmental lesion in the upper aqueduct. Endoscopic third ventriculostomy and biopsy were performed; during surgery, a second small lesion was observed in the infundibular recess. Histologically, the two lesions had the characteristics of low grade astrocytoma, suggesting that the midbrain astrocytoma may have been disseminated via the cerebral spinal fluid to the infundibular recess. Postoperatively this patient received radiotherapy for nearly one month. Although patients with these tumors are not usually administered adjunctive therapy, radiation and, combined modality therapy, including surgery, radiotherapy, and chemotherapy, may be beneficial in patients with midbrain gliomas with dissemination.

Expression of metastasis-associated gene-1 is associated with bone invasion and tumor stage in human pituitary adenomas.

BACKGROUND: Metastasis associated gene-1 (MTA1), was initially discovered in aggressive human cancer cell lines and has been subsequently associated with the invasiveness and metastatic potential of cancer cells. MATERIALS AND METHODS: In the present study, we evaluated the expression levels of MTA1 in a cohort of human pituitary tumors (n=95) and examined the relationship between MTA1 expression and the pathological, clinical and aggressiveness of these tumors. RESULTS: MTA1 was expressed at significantly higher levels in large tumors and in those with higher tumor grade. It was also observed that tumors that had invaded the suprasellar bones and tumors that destructed the sella had significantly higher levels than those without bone involvement (p<005). Although there did not appear to exist any relationship between MTA1 and cystic lesions in the tumors, endocrine-active tumors, namely those secreting prolactin, growth hormone, Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH) had significantly lower MTA1 transcript levels than inactive tumors. CONCLUSION: MTA1 is associated with the aggressive nature of pituitary tumors and may be a potential therapeutic target in this tumor type.

The role of claudin-5 in blood-brain barrier (BBB) and brain metastases (review).

Metastatic brain tumours are frequently observed in patients with lung, breast and malignant melanoma and a severe complication of metastatic cancers. With improved primary cancer treatments, including surgery, radiation therapy and chemotherapy, patients are now living longer following initial treatment, compared with previous treatments. Brain metastasis (BM) remains a significant clinical issue. Since BM represents a major therapeutic challenge, it is vital that the mechanisms of interaction between tumour cells and the blood­brain barrier (BBB), as well as the method by which tumour cells establish metastatic tumours in the brain, are understood. A key step in BM is the interaction and penetration of the BBB by cancer cells. The BBB consists of endothelial cells, pericytes, astrocytes and a number of molecular structures between these cells. The BBB relies on the tight junctions (TJs) that are present between the endothelial cells of the brain capillaries to provide a closed environment for the brain. TJs comprise a number of proteins, including occludin, claudins and junctional adhesion molecules (JAMs). Among them, claudins are the key integral proteins that regulate BBB permeability. It has previously been shown that claudin­5, not only regulates paracellular ionic selectivity, but also plays a role in the regulation of tumour cell motility, suggesting that TJs and claudin­5 contribute to the control of BM. This study reviews the role of claudin­5 in the regulation of BBB permeability during the brain metastatic process.

Overexpression of the Notch3 receptor and its ligand Jagged1 in human clinically non-functioning pituitary adenomas.

Human clinically non-functioning pituitary adenomas (NFPAs) primarily cause headaches, visual impairment and hypopituitarism due to the effect of the mass of the tumor. Surgery is the first-line treatment for these tumors. To date, no efficacious medical therapy exists for non-functioning adenomas. Previous studies have demonstrated that the Notch3 receptor is involved in the pathogenesis of various types of malignancies, including human NFPAs. The current study focused on the expression of the Notch3 receptor and its ligand Jagged1 in three types of pituitary adenomas and in the normal pituitary gland. Using quantitative real-time RT-PCR assays and western blot analyses, upregulated Notch3 and Jagged1 were observed in human NFPAs, but not in normal human pituitary glands or in hormone-secreting adenomas. Furthermore, Notch3 was positively correlated with Jagged1 at the mRNA and protein levels. These data indicate that Notch3 and Jagged1 may play an important role in the initiation and proliferation of human non-functioning adenomas, and there may be an interaction between Notch3 and Jagged1 in this process. Our study further elucidates the role of the Notch3 signaling pathway in the tumorigenesis of human NFPAs and provides a potential therapeutic target for the medical treatment of these tumors.

Expression of the mTOR pathway regulators in human pituitary adenomas indicates the clinical course.

Pituitary ademonas are benign tumours with different biological behaviour, especially with regard to tumour size, invasion, endocrine function, intratumour cystic lesion and apoplexy. There is little understanding of the growth and the control of progression of pituitary tumours. In the present study, we investigated the expression of mammalian target of rapamycin (mTOR) pathway regulators, in clinical pituitary adenomas. Pituitary adenomas from 95 patients were included in the study. Fresh pituitary tumours were obtained immediately after surgery and processed for histological, immunohistological and molecular based analyses. Histolopathological and clinical information including tumour stage, invasion characteristic and endocrine status were analysed against the gene transcript expression of mTOR, RAPTOR and RICTOR. There was a stepwise and significantly increased relation-ship between RICTOR expression and tumour size, namely p=0.0012 and p=0.0055 for tumours 1-2 cm and tumours >3 cm compared with tumours <1 cm respectively. Significantly higher levels of mTOR were seen in tumours with cystic lesions (p=0.044). There was no significant correlation between mTOR, RAPTOR and RICTOR and tumour apoplexy, nor a correlation between mTOR, RAPTOR and RICTOR with suprasephanous spread and sella floor destruction. However, pituitary tumours with cavernous sinus invasion, namely Knosp stage 3-4 had significantly lower levels of RAPTOR than those of Knosp stage 1-2 (p=0.01). A similar but statistically insignificant trend was seen with RICTOR. Using modified Hardy's staging, it was found that there was a significant correlation between tumour stage and RAPTOR and RICTOR expression. mTOR and RAPTOR levels differed in tumours with different endocrine functions, although no statistical difference was observed. However, Growth Hormone (GH) -, Follicle-Stimulating Hormone (FSH)-, Thyroid Stimulating Hormone (TSH)-secreting tumours had significantly lower levels of RICTOR compared with nonfunctional tumours. Finally, levels of mTOR were found to be significantly correlated with levels of both RAPTOR and RICTOR. It is noteworthy that RAPTOR and RICTOR levels were also significantly correlated. In conclusion, mTOR pathway regulators, mTOR, RAPTOR and RICTOR are significantly correlated with the invasion, staging, and tumour growth of pituitary adenomas and thus have an important predictive and prognostic value in patients with pituitary adenoma.

Vascular endothelial growth inhibitor (VEGI) is an independent indicator for invasion in human pituitary adenomas.

Pituitary ademonas are benign tumours from the pituitary gland but may have an invasive and destructive growth pattern. There is little understanding of the growth and progression control of pituitary tumours. In the present study, we investigated the expression of vascular endothelial growth inhibitor (VEGI), a vascular endothelial growth and apoptosis regulator and VEGI receptor Death Receptor-3 (DR3), in clinical pituitary tumours. Pituitary tumours from 95 patients were included in the study. Fresh pituitary tumours were obtained immediately after surgery and processed for histological and molecular-based analyses. Histopathological and clinical information including tumour size, tumour invasion and endocrine status were analyzed against the gene transcript expression of VEGI, DR3 and VEGF. VEGI and VEGF family and VEGF receptors were quantitatively determined for their gene transcript expression. The expression levels of VEGI were significantly lower in pituitary tumours which invaded the sella floor, and with suprasellar extension than in non-invasive tumours (p=0.0073). VEGI levels were also negatively correlated with cavernous sinus invasion stage (p<0.0001), in that a high level of VEGI was associated with low tumour grade. Multivariate analysis indicated that VEGI is an independent factor predictive of invasion (p=0.05). It was further demonstrated that the relationship between VEGI and pituitary tumour invasion were independent of the expression of VEGF and its receptors. Low levels of VEGI transcripts were associated with the intratumoural haemorrhage (p=0.05). Out of all the pituitary tumours, 59 were non-functional. Out of the functional tumours, it was found that follicle stimulating hormone (FSH)-expressing and gonadotrophic tumours tended to have markedly low levels of VEGI transcripts, compared with non-functional tumours (p=0.0026 and p=0.003, respectively). The opposite was seen with thyroid-stimulating hormone (TSH)-secreting tumours. Levels of DR3 in tumours with sella destruction were also lower than in those without destruction. VEGI, possibly via DR3, suppresses the aggressive nature of pituitary tumours and its expression level is closely linked to the invasion and destruction of the suprasellar and sella regions. It also has implications for the endocrine nature of these tumours. VEGI thus has an important predictive and prognostic value in patients with pituitary tumours.