VHL Mutations Research Articles

A case of ovarian mesothelioma with VHL mutation diagnosed by immunohistochemistry and literature review

The malignant mesothelioma mainly develops in the pleura and peritoneum, while primary ovarian mesothelioma is very rare. Here, we report the first case of primary ovarian mesothelioma (clear cell variant) with VHL mutations in the world based on the results of histomorphology, immunohistochemistry, and genetic testing. This is an extremely rare type of tumor that has not been reported so far. Through the literature search, we reviewed primary ovarian mesothelioma, focusing on its differential diagnosis and molecular genetics. The purpose of this paper is to deepen the flexible selection and application of immunohistochemical markers in mesothelioma, so as to reduce missed diagnosis and misdiagnosis.

Atractylenolide I inhibits angiogenesis and reverses sunitinib resistance in clear cell renal cell carcinoma through ATP6V0D2-mediated autophagic degradation of EPAS1/HIF2α

ABSTRACT Clear cell renal cell carcinoma (ccRCC) is tightly associated with VHL (von Hippel-Lindau tumor suppressor) mutation and dysregulated angiogenesis. Accumulating evidence indicates that antiangiogenic treatment abolishing tumor angiogenesis can achieve longer disease-free survival in patients with ccRCC. Atractylenolide I (ATL-I) is one of the main active compounds in Atractylodes macrocephala root extract and exhibits various pharmacological effects, including anti-inflammatory and antitumor effects. In this study, we revealed the potent antitumor activity of ATL-I in ccRCC. ATL-I exhibited robust antiangiogenic capacity by inhibiting EPAS1/HIF2α-mediated VEGFA production in VHL-deficient ccRCC, and it promoted autophagic degradation of EPAS1 by upregulating the ATPase subunit ATP6V0D2 (ATPase H+ transporting V0 subunit d2) to increase lysosomal function and facilitated fusion between autophagosomes and lysosomes. Mechanistically, ATP6V0D2 directly bound to RAB7 and VPS41 and promoted the RAB7-HOPS interaction, facilitating SNARE complex assembly and autophagosome-lysosome fusion. Moreover, ATP6V0D2 promoted autolysosome degradation by increasing the acidification and activity of lysosomes during the later stages of macroautophagy/autophagy. Additionally, we found that ATL-I could decrease the level of EPAS1, which was upregulated in sunitinib-resistant cells, thus reversing sunitinib resistance. Collectively, our findings demonstrate that ATL-I is a robust antiangiogenic and antitumor lead compound with potential clinical application for ccRCC therapy.

VHL missense mutation delineate aggressive clear cell renal cell carcinoma subtype with favorable immunotherapeutic response

Backgroundvon Hippel-Lindau (VHL) harbors the highest mutational frequency in clear cell renal cell carcinoma (ccRCC). Although VHL mutational subtypes exert diverse impacts on the functionality of the VHL protein, the...

8623 Atypical VHL Genetic Variant Causing Paraganglioma

Abstract Disclosure: G. Mangu: None. J.J. Faria Briceno: None. R. Yatavelli: None. Abstract: Pheochromocytomas and paragangliomas (PPGLs) are rare chromaffin cell tumors that originate from the adrenal medulla and extra-adrenal paraganglia respectively. Previous studies have shown that incidental PPGLs are seen in older patients with mild symptoms. They have lower levels of plasma catecholamines and lower incidence of malignancy than patients with nonincidental PPGLs. We report a case of an incidental paraganglioma in a young female with atypical pathogenic variant in the VHL gene which is known to cause familial erythrocytosis but NOT VHL syndrome or PPGL. Case Presentation: A 33-year-old African American female with no significant medical history presented to the emergency room with the chief complaint of right lower quadrant pain for 2 days, which started with her menstruation. The vitals were BP 128/67, pulse 67 and physical examination was unremarkable. CT showed a 4.0 x 3.0 cm heterogenous enhancing left adrenal mass and MRI with adrenal protocol revealed 3.4 x 3.1 cm mass consistent with pheochromocytoma. Labs revealed elevated plasma nor metanephrines and 24-hour urine normetanephrines were 1020 mcg. She was asymptomatic without hypertension, palpitations, or chest pain. She underwent laparoscopic left adrenalectomy after appropriate alpha blockade. The pathology report showed left periadrenal paraganglioma with immunohistochemistry staining significant for Carbonic anhydrase IX (CAIX) membranous expression which is mostly seen in paragangliomas associated with von Hippel-Lindau syndrome. Clinically, she did not have any stigmata for hereditary PPGL syndrome. Her genetic testing revealed a pathogenic heterozygous variant in the VHL gene, Exon 3, c.598C.T (pArg200Trp), which is a missense variant expected to disrupt VHL protein function. Although she has a germline mutation in VHL, it is not the garden variant which is associated with classic VHL syndrome. It has been reported to cause autosomal recessive erythrocytosis but not PPGL. Conclusion: The pathogenic heterozygous variant in VHL gene, Exon 3, c.598C.T (pArg200Trp) is known to cause autosomal recessive familial erythrocytosis type 2 in the Chuvash population, termed as Chuvash Polycythemia. Our patient did not have polycythemia but had iron deficiency anemia from menorrhagia. Several studies have reported that this variant does not cause VHL syndrome, however it has been reported in a single family with VHL syndrome but WITHOUT pheochromocytoma. To our knowledge, incidental adrenergic paraganglioma associated with this mutation has not been reported in the literature. Presentation: 6/3/2024

12315 Unveiling A Paraganglioma: Catecholamine-Induced Hyperglycemia Masquerading As Type 2 Diabetes Mellitus

Abstract Disclosure: S. Salman: None. M. Hussine: None. J. Tibaldi: None. Background: Excessive catecholamines have been demonstrated to exert adverse effects on insulin homeostasis and carbohydrate metabolism, potentially resulting in the onset of secondary DM. We present a case of a patient who had been previously misdiagnosed with T2DM for an extended period. Clinical Case: A 34-year-old woman with history of T2DM, HTN, and chronic tachycardia on beta blockers, presented with complaints of palpitations, headaches, and abdominal pain for two weeks. Upon admission, she was found to be in DKA, necessitating transient administration of insulin drip. Furthermore, she exhibited persistent tachycardia and intermittent episodes of hypertensive urgency. Notably, thyroid levels revealed euthyroidism. Although DKA resolved, her fasting blood sugar levels remained elevated and refractory to escalating insulin therapy. CT abdomen with contrast revealed a large enhancing mass in the RUQ. MRI abdomen confirmed an 8.1 cm heterogeneously enhancing T2 hyperintense mass located in the RUQ, abutting the right hepatic lobe, right adrenal gland, extrahepatic biliary ducts, and adjacent vessels. Given suspicions of a neuroendocrine tumor, she was transferred to the surgical service for tumor excision. Hormonal analysis revealed elevations in plasma metanephrines (620 pg/mL, n 0-88 pg/mL), plasma normetanephrines (9954 pg/mL, n 0-210.1 pg/mL), 24-hr urine normetanephrines (10,952 μg/24hr, n 110-720 μg/24hr) and 24-hr urine metanephrines (1406 μg/24hr, n 35-278 μg/24hr). Additionally, she exhibited elevated 24-hr urine epinephrine fraction (218 μg/g Cr, 0-20 μg/g Cr) and 24-hr urine norepinephrine fraction (2775 μg/g Cr, 0-45 μg/g Cr). Preoperatively, appropriate alpha and beta blockade were administered, followed by successful retroperitoneal tumor resection. Postoperatively, her glucose levels normalized without the need for further insulin therapy, and no episodes of hypoglycemia were reported. Histopathological examination of the excised mass revealed an 11 cm sympathetic paraganglioma with retention of SDHB staining. Genetic testing for SDHB, SDHD, VHL, and RET mutations is pending. Conclusion: This case underscores the potential oversight of pheochromocytomas and paragangliomas due to their nonspecific symptomatology, often mimicking more prevalent conditions, thereby presenting diagnostic challenges. The catecholamines secreted by these tumors can lead to both impaired insulin secretion and increased insulin resistance, resulting in clinically significant manifestations. The exact mechanism underlying the glycemic dysregulation remains controversial, necessitating further investigation through large-scale multicenter prospective studies to enhance understanding and inform diagnostic and therapeutic strategies for these tumors, which can manifest with severe and potentially fatal glycemic disturbances. Presentation: 6/1/2024

Network modeling links kidney developmental programs and the cancer type-specificity of VHL mutations

Elucidating the molecular dependencies behind the cancer-type specificity of driver mutations may reveal new therapeutic opportunities. We hypothesized that developmental programs would impact the transduction of oncogenic signaling activated by a driver mutation and shape its cancer-type specificity. Therefore, we designed a computational analysis framework by combining single-cell gene expression profiles during fetal organ development, latent factor discovery, and information theory-based differential network analysis to systematically identify transcription factors that selectively respond to driver mutations under the influence of organ-specific developmental programs. After applying this approach to VHL mutations, which are highly specific to clear cell renal cell carcinoma (ccRCC), we revealed important regulators downstream of VHL mutations in ccRCC and used their activities to cluster patients with ccRCC into three subtypes. This classification revealed a more significant difference in prognosis than the previous mRNA profile-based method and was validated in an independent cohort. Moreover, we found that EP300, a key epigenetic factor maintaining the regulatory network of the subtype with the worst prognosis, can be targeted by a small inhibitor, suggesting a potential treatment option for a subset of patients with ccRCC. This work demonstrated an intimate relationship between organ development and oncogenesis from the perspective of systems biology, and the method can be generalized to study the influence of other biological processes on cancer driver mutations.

Botryoid-type Embryonal Rhabdomyosarcoma: A Comprehensive Clinicopathologic and Molecular Appraisal With Cross-comparison to its Conventional-type Counterpart.

Embryonal rhabdomyosarcoma (ERMS) is the most common subtype of RMS, occurring in soft tissue and visceral sites of young children, and is associated with favorable outcomes. A subset occurs in mucosal-lined luminal structures, displaying a unique grape-like growth termed as "botryoid-type." To further delineate the differences between conventional (cERMS) and botryoid-type (bERMS) RMS, we performed a comparative histologic review and comprehensive molecular profiling of 48 cases (25 bERMS and 23 cERMS). All tumors were subjected to a hybridization capture-based targeted matched tumor-normal DNA NGS assay. The mean age was 17 and 7 years for bERMS and cERMS, respectively. Most bERMS were female with a predilection for the gynecologic tract (75%), while cERMS had a slight male predominance and were preferentially located in abdominopelvic and paratesticular sites (30%, each). All bERMS exhibited an exophytic, bulbous architecture accompanied by a subepithelial "cambium layer." Distinctive germline alterations were detected, with DICER1 (18%) and FH (6%) mutations only in bERMS, and rare TP53, VHL, and APC mutations in cERMS. Similarly, contrasting somatic genomic landscapes were observed, with frequent DICER1 (52%, P**<0.0001) and TP53 (36%, P*<0.05) alterations exclusively in bERMS. Cartilaginous differentiation was only observed in DICER1-mutated bERMS. All patients had longitudinal follow-up. bERMS patients with somatic/germline DICER1 mutations showed significantly improved recurrence-free survival compared with that of DICER1-wild type patients (P*<0.05). Moreover, bERMS showed improved disease-specific survival compared with that of cERMS, with 8% versus 30% (P*<0.05) dead of disease, respectively. In summary, we compare the molecular underpinnings of the largest cohort of bERMS and cERMS with targeted DNA sequencing and long-term follow-up data. Our findings reveal divergent genomic topographies between the 2 groups, with bERMS showing unique germline and somatic abnormalities, including enrichment in DICER1 and TP53 alterations, and a trend towards improved survival.

11 Tumor evolution of brain-specific tropism in metastatic renal cell carcinoma

Abstract Background Brain metastases (BMets) pose a clinical challenge in the management of patients (pts) with metastatic renal cell carcinoma (RCC), leading to significant morbidity and mortality. Herein, we sought to comprehensively characterize the molecular landscape of BMets in RCC. Methods We performed panel-based DNA (DNAseq) and whole transcriptome (RNAseq) sequencing to analyze BMets, matched non-Brain metastases (nBMets), and matched primary renal tumors (PRT) from pts who underwent surgical resection of BMet(s) from RCC at our institution. Results Our cohort consisted of 95 samples from 53 patients (BMets = 54, nBMets = 14, PRT = 27) with clear cell histology in 45 pts (84.9%). DNAseq was available on 85 samples (50 pts). Patient-level mutations revealed recurring mutations in VHL (18 pts, 36%), TP53 (n = 12 pts, 24%), PBRM1 (12 pts, 24%), SETD2 (12 pts, 24%), and BAP1 (4 pts, 8%). Mutations within the MTOR signaling pathway were enriched, with 25 pts (50%) having at least one mutation in PTEN (12 pts, 24%), TSC1 (4 pts, 8%), TSC2 (5 pts, 10%), or MTOR (9 pts, 18%). Copy number analyses revealed frequent deletions in chr14q21 (34 pts, 68%) and chr9p21 (35 pts, 70%) and gains in chr20q13 (n = 31, 62%) and chr7p15 (n = 31, 62%). At the sample-level, PTEN mutations were more common in BMets (11 pts, 22.9%) vs nBMets (0 pts) and PRTs (3 pts, 12%, p = 0.124), as were deletions in chr13q22 (BMets = 13pts [26.5%], nBMet = 1pts [8.3%], PRT = 1 [4%]; p = 0.036) and gains in chr20q13 (BMets = 30pts [61.2%], nBMet = 4pts [33.3%], PRT = 8 [32%]; p = 0.03). Deletions in chr9p21 were enriched in BMets (32, 65.3%) and nBMets (8, 66.7%) relative to PRTs (7, 28%, p = 0.006), whereas other copy number alterations and somatic mutations exhibited similar proportions across specimen sites. Differential expression analysis performed on 86 samples (51 pts) identified 806 differentially expressed genes (DEGs) between BMets and PRT (adjusted [adj.] p &amp;lt; 0.05) and 399 DEGs between BMet and nBMets (adj. p &amp;lt; 0.05). Gene set enrichment analysis of MSigDB Hallmark gene sets revealed upregulation of MTORC1 signaling, glycolysis, and MYC targets in BMets comparted to PRT and nBMETs (adj. p &amp;lt;0.0001). In contrast, immune-related gene sets, such as interferon-alpha, interferon-gamma, and tumor necrosis factor-alpha, were enriched in PRT relative to BMets (adj. p &amp;lt;0.0001), but not nBMETs (adj. p &amp;gt; 0.05). CIBERSORT cellular deconvolution analysis comparing BMets with PRT revealed decreased proportions of M1 macrophages (p = 0.0003) and CD8+ T-cells (p = 0.0106), but an increased proportion of M2 macrophages (p = 0.0009). Conclusions RCC with brain metastases are characterized by distinct copy number alterations, enrichment of MTOR pathway mutations, MTOR pathway hyperactivation, and an immunosuppressive tumor milieu. These findings may hold therapeutic implications of MTOR pathway inhibition and immune modulators in treating RCC BMets.

Concurrent multiple cerebral cavernous malformations and cauda equina paraganglioma: illustrative case.

Cauda equina neuroendocrine tumors (CENETs), previously known as cauda equina paragangliomas, and multiple cerebral cavernous malformations (CCMs) are uncommon conditions affecting the central nervous system. To the authors' knowledge, they have not been reported in the same patient. The authors present the case of a 45-year-old male with CENET and concurrent incidental MRI findings of multiple CCMs. Familial CCMs are associated with mutations in the KRIT1 (CCM1), MGC4607 (CCM2), and PDCD10 (CCM3) genes. Peripheral paragangliomas have been associated with mutations in succinate dehydrogenase (SDHx), RET (multiple endocrine neoplasia 2), VHL (von Hippel-Lindau syndrome), and NF1 (neurofibromatosis type 1) genes. Except for a single case, cauda equina paragangliomas have not been associated with any underlying genetic mutations. It is unclear whether the co-occurrence of these two rare conditions in the same patient is coincidental or suggests a possible shared pathogenesis. https://thejns.org/doi/10.3171/CASE24102.

Predicting tumor mutation burden and VHL mutation from renal cancer pathology slides with self-supervised deep learning.

Tumor mutation burden (TMB) and VHL mutation play a crucial role in the management of patients with clear cell renal cell carcinoma (ccRCC), such as guiding adjuvant chemotherapy and improving clinical outcomes. However, the time-consuming and expensive high-throughput sequencing methods severely limit their clinical applicability. Predicting intratumoral heterogeneity poses significant challenges in biology and clinical settings. Our aimed to develop a self-supervised attention-based multiple instance learning (SSL-ABMIL) model to predict TMB and VHL mutation status from hematoxylin and eosin-stained histopathological images. We obtained whole slide images (WSIs) and somatic mutation data of 350 ccRCC patients from The Cancer Genome Atlas for developing SSL-ABMIL model. In parallel, 163 ccRCC patients from Clinical Proteomic Tumor Analysis Consortium cohort was used as independent external validation set. We systematically compared three different models (Wang-ABMIL, Ciga-ABMIL, and ImageNet-MIL) for their ability to predict TMB and VHL alterations. We first identified two groups of populations with high- and low-TMB (cut-off point = 0.9). In two independent cohorts, the Wang-ABMIL model achieved the highest performance with decent generalization performance (AUROC = 0.83 ± 0.02 and 0.8 ± 0.04 in predicting TMB and VHL, respectively). Attention heatmaps revealed that the Wang-ABMIL model paid the highest attention to tumor regions in high-TMB patients, while in VHL mutation prediction, non-tumor regions were also assigned high attention, particularly the stromal regions infiltrated by lymphocytes. Our results indicated that SSL-ABMIL can effectively extract histological features for predicting TMB and VHL mutation, demonstrating promising results in linking tumor morphology and molecular biology.

Whole genome sequencing refines stratification and therapy of patients with clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most common form of kidney cancer, but a comprehensive description of its genomic landscape is lacking. We report the whole genome sequencing of 778 ccRCC patients enrolled in the 100,000 Genomes Project, providing for a detailed description of the somatic mutational landscape of ccRCC. We identify candidate driver genes, which as well as emphasising the major role of epigenetic regulation in ccRCC highlight additional biological pathways extending opportunities for therapeutic interventions. Genomic characterisation identified patients with divergent clinical outcome; higher number of structural copy number alterations associated with poorer prognosis, whereas VHL mutations were independently associated with a better prognosis. The observations that higher T-cell infiltration is associated with better overall survival and that genetically predicted immune evasion is not common supports the rationale for immunotherapy. These findings should inform personalised surveillance and treatment strategies for ccRCC patients.

Saturation genome editing maps the functional spectrum of pathogenic VHL alleles

To maximize the impact of precision medicine approaches, it is critical to identify genetic variants underlying disease and to accurately quantify their functional effects. A gene exemplifying the challenge of variant interpretation is the von Hippel–Lindautumor suppressor (VHL). VHL encodes an E3 ubiquitin ligase that regulates the cellular response to hypoxia. Germline pathogenic variants in VHL predispose patients to tumors including clear cell renal cell carcinoma (ccRCC) and pheochromocytoma, and somatic VHL mutations are frequently observed in sporadic renal cancer. Here we optimize and apply saturation genome editing to assay nearly all possible single-nucleotide variants (SNVs) across VHL’s coding sequence. To delineate mechanisms, we quantify mRNA dosage effects and compare functional effects in isogenic cell lines. Function scores for 2,268 VHL SNVs identify a core set of pathogenic alleles driving ccRCC with perfect accuracy, inform differential risk across tumor types and reveal new mechanisms by which variants impact function. These results have immediate utility for classifying VHL variants encountered clinically and illustrate how precise functional measurements can resolve pleiotropic and dosage-dependent genotype–phenotype relationships across complete genes.

Histone lactylation-related genes correlate with the molecular patterns and functions of cancer-associated fibroblasts and have significant clinical implications in clear cell renal cell carcinoma

Recent research emphasised the indispensable role of histone lactylation in the activation of hepatic stellate cells. The VHL mutation is extremely common in clear cell renal cell carcinoma, which normally causes a metabolic shift in cancer cells and increases lactate production, eventually creating a lactate-enriched tumour microenvironment. Cancer-associated fibroblasts (CAFs) promote tumour progression, which is also vital in clear cell renal cell carcinoma. Therefore, this study investigated histone lactylation in CAFs and its impact on patient survival. Multiomics technology was employed to determine the role of histone lactylation-related genes in the evolution of CAFs which correlated with the function and molecular signatures of CAFs. The results suggested that TIMP1 was the hub gene of histone lactylation-related genes in clear cell renal cell carcinoma.

Mutational profile of primary clear cell renal cell carcinoma predicts recurrence and potential candidacy for adjuvant immune checkpoint inhibition.

The risk of recurrence after nephrectomy for primary clear cell renal cell carcinoma (ccRCC) is estimated in daily practice solely based on clinical criteria. The aim of this study was to assess the prognostic relevance of common somatic mutations with respect to tumor aggressiveness and outcomes of ccRCC patients after definitive treatment. Primary tumors from 37 patients with ccRCC who underwent radical nephrectomy were analyzed for presence of somatic mutations using a 15-gene targeted next-generation sequencing (NGS) panel. Associations to histopathologic characteristics and outcomes were investigated in the study cohort (n=37) and validated in The Cancer Genome Atlas (TCGA) ccRCC cohort (n=451). VHL was the most frequently mutated gene (51%), followed by PBRM1 (27%), BAP1 (13%), SETD2 (13%), KDM5C (5%), ATM (5%), MTOR (5%), and PTEN (3%). One-third of patients did not have any somatic mutations within the 15-gene panel. The vast majority of tumors harboring no mutations at all or VHL-only mutations (51%) were more frequently of smaller size (pT1-2) and earlier stage (I/II), whereas presence of any other gene mutations in various combinations with or without VHL was enriched in larger (pT3) and higher stage tumors (III) (p=0.02). No recurrences were noted in patients with unmutated tumors or VHL-only mutations as opposed to three relapses in patients with non- VHL somatic mutations (p=0.06). Presence of somatic mutations in PBRM1, BAP1, SETD2, KDM5C, ATM, MTOR, or PTEN genes in 451 TCGA ccRCC patients was associated with a significantly shorter disease-free survival (DFS) compared to those with unaltered tumors (q=0.01). Preliminary findings from this ongoing study support the prognostic value of non- VHL mutations including PBRM1, BAP1, SETD2, KDM5C, ATM, MTOR, and PTEN in primary ccRCC tumors as surrogates of earlier recurrence and potential selection for adjuvant immune checkpoint inhibition.

Tumor evolution of brain-specific tropism in metastatic renal cell carcinoma.

4530 Background: Brain metastases (BMets) pose a clinical challenge in the management of patients (pts) with metastatic renal cell carcinoma (RCC), leading to significant morbidity and mortality. Herein, we sought to comprehensively characterize the molecular landscape of BMets in RCC. Methods: We performed panel-based DNA (DNAseq) and whole transcriptome (RNAseq) sequencing to analyze BMets, matched non-Brain metastases (nBMets), and matched primary renal tumors (PRT) from pts who underwent surgical resection of BMet(s) from RCC at our institution. Results: Our cohort consisted of 95 samples from 53 patients (BMets = 54, nBMets = 14, PRT = 27) with clear cell histology in 45 pts (84.9%). DNAseq was available 85 samples (50 pts). Patient-level mutations revealed recurring mutations in VHL(18 pts, 36%), TP53 (n = 12 pts, 24%), PBRM1(12 pts, 24%), SETD2(12 pts, 24%), and BAP1(4 pts, 8%). Mutations within the MTOR signaling pathway were enriched, with 25 pts (50%) having at least one mutation in PTEN (12 pts, 24%), TSC1 (4 pts, 8%), TSC2 (5 pts, 10%), or MTOR (9 pts, 18%). Copy number analyses revealed frequent deletions in chr14q21 (34 pts, 68%) and chr9p21 (35 pts, 70%) and gains in chr20q13 (n = 31, 62%) and chr7p15 (n = 31, 62%). At the sample-level, PTEN mutations were more common in BMets (11 pts, 22.9%) vs nBMets (0 pts) and PRTs (3 pts, 12%, p = 0.124), as were deletions in chr13q22 (BMets = 13pts [26.5%], nBMet = 1pts [8.3%], PRT = 1 [4%]; p = 0.036) and gains in chr20q13 (BMets = 30pts [61.2%], nBMet = 4pts [33.3%], PRT = 8 [32%]; p = 0.03). Deletions in chr9p21 were enriched in BMets (32, 65.3%) and nBMets (8, 66.7%) relative to PRTs (7, 28%, p = 0.006), whereas other copy number alterations and somatic mutations exhibited similar proportions across specimen sites. Differential expression analysis performed on 86 samples (51 pts) identified 806 differentially expressed genes (DEGs) between BMets and PRT (adjusted [adj.] p &lt; 0.05) and 399 DEGs between BMet and nBMets (adj. p &lt; 0.05). Gene set enrichment analysis of MSigDB Hallmark gene sets revealed upregulation of MTORC1 signaling, glycolysis, and MYC targets in BMets comparted to PRT and nBMETs (adj. p &lt;0.0001). In contrast, immune-related gene sets, such as interferon-alpha, interferon-gamma, and tumor necrosis factor-alpha, were enriched in PRT relative BMets (adj. p &lt;0.0001), but not nBMETs (adj. p &gt; 0.05). CIBERSORT cellular deconvolution analysis comparing BMets with PRT revealed decreased proportions of M1 macrophages (p = 0.0003) and CD8+ T-cells (p = 0.0106), but an increase proportion of M2 macrophages (p = 0.0009). Conclusions: RCC with brain metastases are characterized by distinct copy number alterations, enrichment of MTOR pathway mutations, MTOR pathway hyperactivation, and an immunosuppressive tumor milieu. These findings may hold therapeutic implications of MTOR pathway inhibition and immune modulators in treating RCC BMets.

Shared chromosome 21q loss in a mixed subtype renal cell carcinoma: composite or collision tumor?

Clear cell renal cell carcinoma (CCRCC) and papillary renal cell carcinoma (PRCC) are the two most frequentlyencountered subtypes of renal cell carcinoma (RCC). Rarely, these two entities are identified intermingled within thesame mass and have been labeled either collision tumors juxtaposed by random chance or composite tumors thathave arisen from a common tumorigenic precursor cell. Regarding this distinction, authors have commonly reliedupon macroscopic, histologic, and clinicopathologic findings, which may be prone to subjectivity. Objectivemolecular evidence has been lacking. We present a renal tumor showing a mixed CCRCC and PRCC withcorroborating histologic, immunophenotypic, chromosomal microarray analysis (CMA), and next-generationsequencing (NGS) analysis for the respective tumor components, including classic findings of chromosome 3p lossand VHL mutation within the CCRCC component and gain of chromosomes 7 and 17 within the PRCC component.Of novel interest, CMA revealed a shared loss of chromosome 21q in both components with no other identifiableshared or overlapping mutations. This report adds unique evidence supporting the possibility of a true compositerenal cell carcinoma composed of two commonly recognized subtypes. This finding may help to inform earlymolecular pathogenetic mechanism of RCC tumorigenesis.

Pancreatic neuroendocrine tumors in French VHL mutation carriers: a multicentric retrospective study.

Von Hippel-Lindau disease (VHL) is a rare autosomal dominant hereditary cancer-predisposition syndrome caused by germline pathogenic variants (PV) in VHL gene. It is associated with a high penetrance of benign and malignant vascular tumors in multiples organs, including pancreatic neuroendocrine tumors (PanNETs), whose long-term natural history is ill-known. Patients with both documented germline PV in VHL gene and PanNETs included in the French PREDIR database between 1995 and 2022 were included. Primary endpoint was the proportion of patients with PanNET-related metastases and secondary endpoint was overall survival (OS). Genotype/phenotype correlations were studied. We included 121 patients with 259 PanNETs. Median age at diagnosis was 38 years. Median follow-up was 89.5 months. PanNET surgical resection was performed in 51 patients. Overall, 29 patients (24%) had metastases (5 synchronous, 10 metachronous), with a higher risk in case of larger PanNET size (p=0.0089; best threshold 28 mm) and grade 2 PanNET (p=0.048), and a pejorative prognostic impact (p=0.043). Patients with PV in VHL exon 1 had larger PanNETs (p=0.018), more often metastatic disease (48% vs 11.5%; p < 0.001) and a trend toward shorter OS (p=0.16). The risk of metastases associated to VHL-related PanNETs remains low (24%) but increases with tumor size >28 mm, higher grade and in case of PV located VHL exon 1. These data might help improving the management of these patients, who should be referred to an expert center.

Von Hippel-Lindau protein signalling in clear cell renal cell carcinoma.

The distinct pathological and molecular features of kidney cancer in adaptation to oxygen homeostasis render this malignancy an attractive model for investigating hypoxia signalling and potentially developing potent targeted therapies. Hypoxia signalling has a pivotal role in kidney cancer, particularly within the most prevalent subtype, known as renal cell carcinoma (RCC). Hypoxia promotes various crucial pathological processes, such as hypoxia-inducible factor (HIF) activation, angiogenesis, proliferation, metabolic reprogramming and drug resistance, all of which contribute to kidney cancer development, growth or metastasis formation. A substantial portion of kidney cancers, in particular clear cell RCC(ccRCC), are characterized by a loss of function of Von Hippel-Lindautumour suppressor (VHL), leading to the accumulation of HIF proteins, especially HIF2α, a crucial driver of ccRCC. Thus, therapeutic strategies targeting pVHL-HIF signalling have been explored in ccRCC, culminating in the successful development of HIF2α-specific antagonists such as belzutifan (PT2977), an FDA-approved drug to treat VHL-associated diseases including advanced-stage ccRCC. An increased understanding of hypoxia signalling in kidney cancer came from the discovery of novel VHL protein (pVHL) targets, and mechanisms of synthetic lethality with VHL mutations. These breakthroughs can pave the way for the development of innovative and potent combination therapies in kidney cancer.

Screening and surveillance recommendations for central nervous system hemangioblastomas in pediatric patients with Von Hippel-Lindau disease

PurposeVon Hippel-Lindau (VHL) disease is an autosomal-dominantly inherited tumor predisposition syndrome. One of the most common tumors are central nervous system (CNS) hemangioblastomas. Recommendations on the initiation and continuation of the screening and surveillance program for CNS tumors in pediatric VHL patients are based on small case series and thus low evidence level. To derive more robust screening recommendations, we report on the largest monocentric pediatric cohort of VHL patients.MethodsWe performed a retrospective analysis on a pediatric cohort of 99 VHL patients consulted at our VHL center from 1992 to 2023. Clinical, surgical, genetic, and imaging data were collected and statistically analyzed.Results42 patients (50% male) developed CNS hemangioblastomas, of whom 18 patients (56% male) underwent hemangioblastoma surgery (mean age at first surgery: 14.9 ± 1.9 years; range 10.2–17). The first asymptomatic patient was operated on at the age of 13.2 years due to tumor progress. Truncating VHL mutation carriers had a significantly higher manifestation rate (HR = 3.7, 95% CI: 1.9–7.4, p < 0.0001) and surgery rate (HR = 3.3, 95% CI: 1.2–8.9, p = 0.02) compared with missense mutation carriers.ConclusionWe recommend starting MRI imaging at the age of 12 years with examination intervals every (1-) 2 years depending on CNS involvement. Special attention should be paid to patients with truncating variants. Affected families should be educated regularly on potential tumor-associated symptoms to enable timely MRI imaging and eventually intervention, as CNS hemangioblastoma may develop before screening begins.German clinical trials Register registration numberDRKS00029553, date of registration 08/16/2022, retrospectively registered.

VHL mutation drives human clear cell renal cell carcinoma progression through PI3K/AKT-dependent cholesteryl ester accumulation

Cholesteryl ester (CE) accumulation in intracellular lipid droplets (LDs) is an essential signature of clear cell renal cell carcinoma (ccRCC), but its molecular mechanism and pathological significance remain elusive. Enabled by the label-free Raman spectromicroscopy, which integrated stimulated Raman scattering microscopy with confocal Raman spectroscopy on the same platform, we quantitatively analyzed LD distribution and composition at the single cell level in intact ccRCC cell and tissue specimens in situ without any processing or exogenous labeling. Since we found that commonly used ccRCC cell lines actually did not show the CE-rich signature, primary cancer cells were isolated from human tissues to retain the lipid signature of ccRCC with CE level as high as the original tissue, which offers a preferable cell model for the study of cholesterol metabolism in ccRCC. Moreover, we established a patient-derived xenograft (PDX) mouse model that retained the CE-rich phenotype of human ccRCC. Surprisingly, our results revealed that CE accumulation was induced by tumor suppressor VHL mutation, the most common mutation of ccRCC. Moreover, VHL mutation was found to promote CE accumulation by upregulating HIFα and subsequent PI3K/AKT/mTOR/SREBPs pathway. Inspiringly, inhibition of cholesterol esterification remarkably suppressed ccRCC aggressiveness invitro and invivo with negligible toxicity, through the reduced membrane cholesterol-mediated downregulations of integrin and MAPK signaling pathways. Collectively, our study improves current understanding of the role of CE accumulation in ccRCC and opens up new opportunities for treatment. This work was supported by National Natural Science Foundation of China (No. U23B2046 and No. 62027824), National Key R&D Program of China (No. 2023YFC2415500), Fundamental Research Funds for the Central Universities (No. YWF-22-L-547), PKU-Baidu Fund (No. 2020BD033), Peking University First Hospital Scientific and Technological Achievement Transformation Incubation Guidance Fund (No. 2022CX02), and Beijing Municipal Health Commission (No. 2020-2Z-40713).