Tuberous Sclerosis Syndrome Research Articles

Deciphering the physiopathology of neurodevelopmental disorders using brain organoids.

Neurodevelopmental disorders (NDD) encompass a range of conditions marked by abnormal brain development in conjunction with impaired cognitive, emotional, and behavioural functions. Transgenic animal models, mainly rodents, traditionally served as key tools for deciphering the molecular mechanisms driving NDD physiopathology, and significantly contributed to the development of pharmacological interventions aimed at treating these disorders. However, the efficacy of these treatments in humans has proven to be limited, due in part to the intrinsic constraint of animal models to recapitulate the complex development and structure of the human brain but also to the phenotypic heterogeneity found between affected individuals. Significant advancements in the field of induced pluripotent stem cells (iPSC) offer a promising avenue for overcoming these challenges. Indeed, the development of advanced differentiation protocols for generating iPSC-derived brain organoids gives the unprecedented opportunity to explore the human neurodevelopment. This review provides an overview of how 3D brain organoids have been used to investigate various NDD (i.e., Fragile X syndrome, Rett syndrome, Angelman syndrome, microlissencephaly, Prader-Willi syndrome, Timothy Syndrome, tuberous sclerosis syndrome), and elucidate their pathophysiology. We also discuss the benefits and limitations of employing such innovative 3D models compared to animal models and 2D cell culture systems, in the realm of personalized medicine.

Positive GPNMB Immunostaining Differentiates Renal Cell Carcinoma With Fibromyomatous Stroma Associated With TSC1/2/MTOR Alterations From Others.

Renal cell carcinoma with fibromyomatous stroma (RCCFMS) include ELOC/TCEB1 -mutated renal cell carcinoma (RCC) and those with TSC1/2 / MTOR alterations. Besides morphologic similarity, most of these tumors is known to be diffusely positive for carbonic anhydrase IX and cytokeratin 7 by immunohistochemistry. We previously showed strong and diffuse expression of GPNMB (glycoprotein nonmetastatic B) in translocation RCC and eosinophilic renal neoplasms with known TSC1/2/MTOR alterations. We retrospectively identified molecularly confirmed cases of TCEB1/ELOC -mutated RCC (7 tumors from 7 patients), and RCCFMS with alterations in TSC1/2/MTOR (6 tumors from 5 patients, 1 patient with tuberous sclerosis syndrome). In addition, we included 7 clear cell papillary renal cell tumors (CCPRCTs) and 8 clear cell RCC, as they can also present morphologic overlap with RCCFMS. Morphologically, RCCs with TSC1/2/MTOR alterations and those with TCEB1/ELOC mutations were indistinguishable and characterized by papillary, nested, or tubular architecture, with tumor cells with clear cytoplasm and low nuclear grade. By immunohistochemistry, cytokeratin 7 was positive in 5/7 (71%) of TCEB1/ELOC -mutated RCCs, 6/6 (100%) of RCCs with TSC1/2/mTOR alterations, and 7/7 (100%) of CCPRCTs ( P =not significant). Carbonic anhydrase IX was positive in 7/7 TCEB1/ELOC -mutated RCCs, 6/6 (100%) of RCCs with TSC1/2/MTOR alterations, and 7/7 (100%) of CCPRCTs ( P =NS). GPNMB was strongly and diffusely positive in all tumors with TSC1/2/MTOR alterations (6/6), while negative in all TCEB1/ELOC -mutated RCCs (0/6), or CCPRCTs (0/7) ( P =0.002). Two of 8 clear cell RCC showed focal weak staining, while 6/8 were negative. In conclusion, the results support the use of GPNMB to distinguish RCCFMS with TSC1/2/MTOR alterations from others with similar morphology.

Factors predicting the active treatment of renal angiomyolipoma: 30 years of experience in two tertiary referral centers.

This study aimed to identify clinical features representing predictive factors of active treatment (AT) compared to active surveillance (AS) for renal angiomyolipoma (AML). From 1990 to 2020, patients referred to two institutions for a renal mass and diagnosed with an AML based on typical features on CT were included in the analysis. The study population was divided into two groups based on the treatment received: active surveillance (AS) or active treatment (AT). Age, gender, tuberous sclerosis syndrome, tumor size, contralateral kidney disease, renal function, year of diagnosis, and symptoms at presentation were assessed as potential predictive factors of active treatment using a logistic regression model in univariate and multivariate analyses. In total, 253 patients (mean age 52.3 ± 15.7 years; 70% women; 70.9% incidentally diagnosed) were included in the analysis. One hundred and nine (43%) received AS, whereas 144 (57%) were actively treated. For univariate analysis, age, tuberous sclerosis complex syndrome, tumor size, symptoms at presentation, and contralateral kidney disease were found to be predictors of AT. Only tumor size (p < 0.001) and the year of diagnosis (p < 0.001) remained significant for multivariable analyses. The likelihood of being managed with AS evolved over the study period and was 50% and 75% when diagnosed before and after 2010, respectively. With respect to size, 4-cm and 6-cm tumors had a probability of 50% and 75% of being treated with AS, respectively. The present analysis from a high-volume institution provides evidence that the management of renal masses with typical radiological features of AML has markedly changed over the last three decades with a trend toward AS over AT. Tumor size and the year of diagnosis were significant factors for the treatment strategies.

Reciprocal effects of mTOR inhibitors on pro-survival proteins dictate therapeutic responses in tuberous sclerosis complex

mTORC1 is aberrantly activated in cancer and in the genetic tumor syndrome tuberous sclerosis complex (TSC), which is caused by loss-of-function mutations in the TSC complex, a negative regulator of mTORC1. Clinically approved mTORC1 inhibitors, such as rapamycin, elicit a cytostatic effect that fails to eliminate tumors and is rapidly reversible. We sought to determine the effects of mTORC1 on the core regulators of intrinsic apoptosis. In TSC2-deficient cells and tumors, we find that mTORC1 inhibitors shift cellular dependence from MCL-1 to BCL-2 and BCL-XL for survival, thereby altering susceptibility to BH3 mimetics that target specific pro-survival BCL-2 proteins. The BCL-2/BCL-XL inhibitor ABT-263 synergizes with rapamycin to induce apoptosis in TSC-deficient cells and in a mouse tumor model of TSC, resulting in a more complete and durable response. These data expose a therapeutic vulnerability in regulation of the apoptotic machinery downstream of mTORC1 that promotes a cytotoxic response to rapamycin.

Abstract LB196: SPR965, a PI3K/mTORC1/C2 inhibitor for treatment of chordoma

Abstract Introduction: Chordoma is a rare tumor with a median survival of 7 years in US. At present, standard treatment involves surgery and/or radiation. Complete surgical resection, however, can be challenging as the tumor is located on the skull base or spine. Moreover, there is currently no approved systemic therapy for advanced chordoma. These challenges have resulted in significant morbidity and a dismal cure rate of approximately 30%, highlighting the need for development of new therapeutic strategies for this orphan disease. Emerging evidence suggests a key role for the PI3K/mTOR pathway in chordoma and numerous reports point to an enrichment of chordoma cases in individuals with tuberous sclerosis syndrome, which is driven by dysregulated mTOR activity. Another study of chordoma tumors from 111 patients demonstrated that the mTOR pathway was activated in 46% of the tumors, and sequencing studies have revealed oncogenic alterations to the PI3K/mTOR pathway in approximately 15-20% of chordomas. We surmised that dual inhibition of both the mTOR and the PI3K pathways may represent a desirable profile as it will not only have the potential to address the effects of activation of both these targets, but also prevent feedback reactivation of the pathway resulting from the inhibition of one or the other. Previously, SPR965 was shown as a potent, selective and orally bioavailable PI3K and mTOR C1/C2 inhibitor with an excellent PK/ADME profile. Methods: SPR965 and comparator compounds were evaluated in vitro in the chordoma cell lines JHC7, U-CH1, and U-CH2 by (Resarufin assay). SPR965 was evaluated in vivo in multiple chordoma PDX models. Results: SPR965 in vitro showed significant effect on cell proliferation with EC50 of 50-90nM. SPR965 was more active at 1uM than PI3K/mTOR inhibitors VS-5584, Bimiralisib, PF-04691502, WYE-687, Dactolisib, and Voxtalisib in the Kinase Chemogenomic Set. SPR965 in vivo monotherapy in SF8894 PDX at 3mg/kg had similar tumor growth inhibition (TGI) to CDK4/6 inhibitor Palbociclib at 50mg/kg. SPR965 combination with Palbocicilib had similar TGI to PI3K inhibitor Buparlisib at 35mg/kg. In CF459 PDX, SPR965 potently inhibited tumor growth at 10mg/kg. TGI% was statistically significant with SPR965 versus untreated controls in both models. Conclusion: In SF8894 PDX model SPR965 was more efficacious as it produced similar tumor growth inhibition at 12- and 17-fold lower dose than Buparlisib (PI3K) and Palbociclib (CDK4/6) respectively, both these compounds are in phase 2 clinical trials. In CF459 PDX model SPR965 exhibited dose-dependent tumor growth inhibition, and at 10mg/kg profoundly slowed tumor growth compared to Palbociclib. Studies are underway to elucidate potential mechanisms of SPR965 sensitivity. SPR965 represents a significant opportunity for development of a targeted therapeutic for chordoma patients. Citation Format: Sundeep Dugar, Somdutta Sen, Paul Maffuid, Dan Freed, Josh Sommer, Edward Anderson, Anthony Hickey. SPR965, a PI3K/mTORC1/C2 inhibitor for treatment of chordoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB196.

Eosinophilic vacuolated tumour of the kidney

Eosinophilic vacuolated tumour (EVT) is one of the emerging entities of renal cell carcinoma. We present a case which we believe is second ever reported case of eosinophilic and vacuolated renal tumour (EVT) arising in setting of tuberous sclerosis syndrome. A 44-year-old male patient with past history (2017) of unclassified renal cell carcinoma of left kidney and known tuberous sclerosis syndrome receiving ongoing tyrosine kinase inhibitor therapy and undergoing radiological surveillance was found to have a 3 cm right renal mass.

Eosinophilic, solid, and cystic renal cell carcinoma (ESC-RCC)

Despite its descriptive name, eosinophilic, solid, and cystic renal cell carcinoma (ESC-RCC) represents adistinctive epithelial renal tumor entity defined by characteristic clinicopathological and molecular features. ESC-RCC occurs predominantly in women and is characterized in the majority of cases by sporadic (somatic) TSC mutations. Asmall subset of cases, however, affects patients with TSC germline mutations (tuberous sclerosis syndrome). TSC mutations have therefore been shown to be pathogenetic in this type of tumor. Most tumors present as small (pT1) well circumscribed but not encapsulated lesions with variable macrocystic spaces on their cut surface. Immunohistochemically, their CD117-/CK7-/CK20+ profile is characteristic. Although the tumor cell nuclei of the ESC-RCC occasionally correspond to ISUP/WHO grade 2-3, these tumors are essentially indolent with aggressive cases being only rarely observed. Single case reports have documented effective treatment of aggressive cases with mTOR inhibitors. ESC-RCC needs to be distinguished from avariety of eosinophilic RCC types with secondary cystic changes including cystic SDH-deficient RCC, the recently proposed eosinophilic vacuolated tumor (EVT; also mTOR-related), oncocytoma, and low-grade oncocytic tumor (LOT). The generally indolent behavior and frequent TSC/mTOR alterations in ESC-RCC, EVT, and some LOTs raise the question of whether these lesions represent independent tumor entities or are merely morphological variants on the spectrum of eosinophilic low-grade TSC/mTOR-related neoplasms.

Interleukin-6 mediates PSAT1 expression and serine metabolism in TSC2-deficient cells

Tuberous sclerosis complex (TSC) and lymphangioleiomyomatosis (LAM) are caused by aberrant mechanistic Target of Rapamycin Complex 1 (mTORC1) activation due to loss of either TSC1 or TSC2 Cytokine profiling of TSC2-deficient LAM patient-derived cells revealed striking up-regulation of Interleukin-6 (IL-6). LAM patient plasma contained increased circulating IL-6 compared with healthy controls, and TSC2-deficient cells showed up-regulation of IL-6 transcription and secretion compared to wild-type cells. IL-6 blockade repressed the proliferation and migration of TSC2-deficient cells and reduced oxygen consumption and extracellular acidification. U-13C glucose tracing revealed that IL-6 knockout reduced 3-phosphoserine and serine production in TSC2-deficient cells, implicating IL-6 in de novo serine metabolism. IL-6 knockout reduced expression of phosphoserine aminotransferase 1 (PSAT1), an essential enzyme in serine biosynthesis. Importantly, recombinant IL-6 treatment rescued PSAT1 expression in the TSC2-deficient, IL-6 knockout clones selectively and had no effect on wild-type cells. Treatment with anti-IL-6 (αIL-6) antibody similarly reduced cell proliferation and migration and reduced renal tumors in Tsc2 +/- mice while reducing PSAT1 expression. These data reveal a mechanism through which IL-6 regulates serine biosynthesis, with potential relevance to the therapy of tumors with mTORC1 hyperactivity.

Surgical treatment of epilepsy at the Russian Children’s Clinical Hospital: substrates and imaging aspects

Introduction. MRI revealing the epileptogenic foci is the central part of the presurgical evaluation of children with focal-resistant epilepsy. Besides that, MRI seems to be a reliable instrument of treatment optimization and good prognosis. Aim. To identify epileptogenic lesions in children with resistant focal epilepsy by high resolution (HR) MRI and comparing obtained data with postsurgical morphology. Materials and methods. We assessed the results of neuroimaging, EEG, clinical neurological status, and postsurgical morphological data in 65 children with focal epilepsy who had undergone antiepileptic surgery in Russian State Children Hospital, neurosurgery department (Moscow, Russia) from 2016 to 2020. Results. The broad spectrum of epileptogenic lesions was revealed by HR MRI, including focal and diffuse cortical dysplasias (44.6%), cortical post hypoxic gliosis (27.7%), glial tumors (7.7%), Rasmussen encephalitis (10.8%), tuberous sclerosis, and Sturge-Weber syndrome (3%), small angiodysplasias (4.6%) and other. Focal cerebral dysplasia had an obvious superiority as the main etiological factor in focal epilepsy and was approved in 33.8% of all patients. In all cases, epilepsy is characterized by frequent and resistant seizures, inflicting motor arrest, and psycho-emotional deterioration. Conclusion. HR MRI and multidisciplinary investigation have to be unchangeable standards in the presurgical evaluation of children with focal epilepsy. This approach’s effectiveness has reassuring confirmation by high level (95.2%) of total coincidence MRI and morphological results.

Structural Abnormalities on MRI in Cases with Epilepsy

Introduction: Many treatable anatomical abnormalities of the brain can cause seizures. The present study was done to determine the role of MRI for evaluation of patients with epilepsy. Subjects and Methods: Patients who presented to our hospital with history of epilepsy. i.e two or more episodes of unproved seizures 24 hours apart, underwent MRI study to assess for abnormalities. Patients of either gender and all age groups who were referred to our department for MRI study were included. Results: Generalized tonic clonic seizures were present in 86% of the population and rest had partial seizures. Using MRI, we arrived at a diagnosis as a cause of seizure in 51.3% of the patients and rest of the 48.7% had a normal MRI study. The most common pathology detected on MRI was infarct with gliosis (24.7%). Less common pathology detected were neurocysticercosis (6.7%), brain atrophy (5.3%), tuberculoma (3.3%), venous thrombosis (2.7%), developmental malformations (2.7%), glioma (1.3%), cavernoma (1.3%), tuberous sclerosis (1.3%), meningioma (0.7%), cerebral abscess (0.7%) and Sturge Weber syndrome (0.7%). Abnormality on MRI was not significantly associated with gender or type of seizure. MR abnormality was observed maximum in patients between 1 to 30 years (30 out of 70 patients i.e. 42.8%) while all the elderly cases showed abnormal MRI, with infract with gliosis being the most common finding. Conclusions : MR imaging should be the first investigation of choice in epileptic syndrome, cerebrovascular disease with seizure, developmental cortical malformations, and vascular malformations.

Abstract B13: Targeting mTOR/JUN/AXL pathway in TSC-related tumors

Abstract Renal angiomyolipoma (AML) and cysts are seen in 70-80% of patients with the human tumor suppressor gene syndrome tuberous sclerosis complex (TSC). Renal cell carcinoma (RCC) also is relatively common in TSC. Although two-hit loss of TSC1/2 is established in AML and TSC-RCC, the mechanisms and signaling pathways underlying TSC tumor development are not well understood. TSC-related tumor models were generated through i.p. tamoxifen (TM) injection (10mg/kg) at embryonic day 17.5 in Tsc2f/fROSA26-CreERT2 (n=24), Tsc2f/f CAG-CreERT2 mice (n=2) and Tsc1f/f CAG-CreERT2 mice (n=19). Extensive TSC-associated kidney papillary RCC (PRCC) and hybrid oncocytic/chromophobe tumors (HOCT) were seen in every kidney of these mice at age of 6 months, confirmed by IHC. A phospho-RTK immunoblot screen was performed using lysates from kidney tumors in comparison to normal kidneys. pAXL levels were ~2.8-fold higher versus normal kidney, whereas other pRTKs showed no apparent change. Immunoblotting confirmed the upregulated levels of both p-AXL (Tyr 702) and total AXL in kidney tumor lysates vs. normal kidneys. Q-RT-PCR of mRNA also showed 2-fold increase in AXL mRNA. Bioinformatic analysis suggested that AXL is a probable target of the transcription factor JUN. RNA-seq data showed that AMLs had the highest level of JUN expression in comparison to 28 different kinds of cancer (from TCGA). JUN was highly expressed in the mouse kidney tumors compared to normal kidneys in both protein and mRNA levels. JUN levels were also assessed using TSC-null cell lines (TSC2-/- angiomyolipoma cells (h), Tsc2-/- renal cell carcinoma cells (m), TSC1-/- bladder cancer cells (h), Tsc1-/- lung cancer cells (m)) versus their TSC add-back counterparts. All TSC-null cells showed a higher level of JUN and AXL compared to their TSC add-back counterparts. Both rapamycin (20nM) and Torin (500nM) treatment of these cell lines for 24h led to a reduction in JUN expression, with a stronger effect from Torin than rapamycin. To identify connections between JUN and AXL, JUN and AXL CRISPR KO were performed in 2 Tsc2-/- renal cell carcinoma cell lines. JUN KO led to a major decrease in AXL expression, and AXL KO led to a decrease of JNK, ERK and JUN. A positive feedback loop may exist between JUN and AXL through JNK and ERK pathway. R428, an inhibitor of AXL, was used to treat our Tsc2f/f ROSA26-CreERT2 mice and Tsc2+/- AJ mice (12.5mg/kg, twice daily, oral gavage, 3 weeks). Kidney tumor volume decreased dramatically compared with vehicle-treated mice in both cohorts (31.38 vs 4.11 mm³, p=0.001; 1.84 vs 0.05 mm³, p=0.02). These findings suggest that JUN and AXL are both upregulated in response to TSC1/TSC2 loss and mTORC1 activation and contribute to tumorigenesis, and that there is potential therapeutic value to targeting these events. Citation Format: Heng Du, Heng-jia Liu, Damir Khabibullin, Mahsa Zarei, John Dreier, Chin-Lee Wu, Elizabeth Henske, David Kwiatkowski. Targeting mTOR/JUN/AXL pathway in TSC-related tumors [abstract]. In: Proceedings of the AACR Special Conference on Targeting PI3K/mTOR Signaling; 2018 Nov 30-Dec 8; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(10_Suppl):Abstract nr B13.

IMPDH inhibitors for antitumor therapy in tuberous sclerosis complex.

Recent studies in distinct preclinical tumor models have established the nucleotide synthesis enzyme inosine-5'-monophosphate dehydrogenase (IMPDH) as a viable target for antitumor therapy. IMPDH inhibitors have been used clinically for decades as safe and effective immunosuppressants. However, the potential to repurpose these pharmacological agents for antitumor therapy requires further investigation, including direct comparisons of available compounds. Therefore, we tested structurally distinct IMPDH inhibitors in multiple cell and mouse tumor models of the genetic tumor syndrome tuberous sclerosis complex (TSC). TSC-associated tumors are driven by uncontrolled activation of the growth-promoting protein kinase complex mechanistic target of rapamycin (mTOR) complex 1 (mTORC1), which is also aberrantly activated in the majority of sporadic cancers. Despite eliciting similar immunosuppressive effects, the IMPDH inhibitor mizoribine, used clinically throughout Asia, demonstrated far superior antitumor activity compared with the FDA-approved IMPDH inhibitor mycophenolate mofetil (or CellCept, a prodrug of mycophenolic acid). When compared directly to the mTOR inhibitor rapamycin, mizoribine treatment provided a more durable antitumor response associated with tumor cell death. These results provide preclinical support for repurposing mizoribine, over other IMPDH inhibitors, as an alternative to mTOR inhibitors for the treatment of TSC-associated tumors and possibly other tumors featuring uncontrolled mTORC1 activity.

Renal cell carcinoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up†.

Renal cell carcinoma (RCC) accounts for 2%–3% of all adultmalignancies, representing the seventh most common cancer inmen and the ninth most common cancer in women [1].Worldwide, there are ∼209000 new cases and 102000 deathsper year. The incidence of all stages of RCC has increased overthe past several years, contributing to a steadily increasing mor-tality rate per unit population. Active and passive cigarettesmoking is an established risk factor for RCC as well as hyper-tension. However, anti-hypertensive medications such as diure-tics are not independently associated with RCC development.RCC also appears to be more common in patients with obesity,end-stage renal failure, acquired renal cystic disease and tuber-ous sclerosis.Approximately 2%–3% of RCC are hereditary and severalautosomal dominant syndromes are described, each with a dis-tinct genetic basis and phenotype, the most common one beingVon Hippel Lindau disease.In recent years, many new genes associated with RCC havebeen reported (such as PBRM1, SETD2, BAP1). Their roles inpathogenesis and as prognostic biomarkers are currently underinvestigation.

Tuberous sclerosis syndrome: a typical case of a rare disease

The article is devoted to a rare hereditary disease from the group of phak omatoses with an autosomal dominant type of inheritance — Pringle — Burnevill disease. The questions of the prevalence of the disease, the variability of the clinical picture, the timeliness of the clinical diagnosis are considered. Particular attention is paid to skin manifestations and their differential diagnosis. A clinical case of this disease is described.

Screening for TSC1 and TSC2 mutations using NGS in Greek children with tuberous sclerosis syndrome.

Tuberous Sclerosis Complex (TSC) is a rare neurocutaneous syndrome inherited by an autosomal dominant manner. The disorder is commonly manifested by the presence of multiple benign tumors located in numerous tissues, including the brain, heart, skin and kidneys. Seizures, autism, developmental and behavioral delay, as well as non-neurological phenotypic findings, are suggestive of TSC. The identification of one pathogenic mutation in either the TSC1 or TSC2 genes is considered to be an independent diagnostic criterion. In our study, seventeen Greek patients, 2yo on average, were analyzed for the presence of pathogenic germline mutations in the aforementioned loci by Next-Generation Sequencing. A TSC1/2 gene panel was designed for the molecular diagnosis of the disease. Patients underwent initial diagnosis based on their clinical symptoms, most frequently involving the presence of skin lesions and/or epilepsy. Only one case was familial. Sixteen different genetic alterations were identified in TSC1 and TSC2 genes in fifteen patients, giving a 88% detection rate by employing NGS technology. Overall, most pathogenic mutations (11/15) identified were located in the TSC2 gene with exon 41 being the most frequent. With respect to genotype-phenotype association, no patient TSC1 (+) developed SEGA or renal cysts. No significant differences were observed between different types of TSC2 mutations and any clinical feature. Sequencing also revealed 18 different SNPs across the TSC1 and 20 across the TSC2 genes. This is the first registry of the genetic profile of TSC patients in Greece using a custom-made gene panel as molecular diagnostic tool.

Pulmonary lymphangioleiomyomatosis associated with aggressive renal angiomyolipoma

ABSTRACTLymphangioleiomyomatosis (LAM) is a rare cystic pulmonary disease that may occur in association with mutations in the tuberous sclerosis genes or arise sporadically. The histologic hallmark of the disease is the “LAM” cell, a spindled to epithelioid smooth muscle-like cell that bears morphologic and immunohistochemical resemblance to the perivascular epithelioid cell tumors (PEComas). The origin of the “LAM” cell is unknown; emerging theories suggest that a member of the PEComa family, the renal angiomyolipoma, may be the primary source and that both LAM and angiomyolipomas are associated with the genetic syndrome tuberous sclerosis. We present a young woman with LAM with an aggressive renal angiomyolipoma confirmed at autopsy.

Oncogenic effects of urotensin-II in cells lacking tuberous sclerosis complex-2.

Lymphangioleiomyomatosis (LAM) is a destructive lung disease that can arise sporadically or in adults suffering from the tumor syndrome tuberous sclerosis complex (TSC). Microscopic tumors (‘LAM nodules’) in the lung interstitium arise from lymphatic invasion and metastasis. These consist of smooth muscle-like cells (LAM cells) that exhibit markers of neural crest differentiation and loss of the tumor suppressor protein ‘tuberous sclerosis complex-2’ (TSC2). Consistent with a neural phenotype, expression of the neuropeptide urotensin-II and its receptor was detected in LAM nodules. We hypothesized that loss of TSC2 sensitizes cells to the oncogenic effects of urotensin-II. TSC2-deficient Eker rat uterine leiomyoma ELT3 cells were stably transfected with empty vector or plasmid for the expression of TSC2. Urotensin-II increased cell viability and proliferation in TSC2-deficient cells, but not in TSC2-reconstituted cells. When exposed to urotensin-II, TSC2-deficient cells exhibited greater migration, anchorage-independent cell growth, and matrix invasion. The effects of urotensin-II on TSC2-deficient cells were blocked by the urotensin receptor antagonist SB657510, and accompanied by activation of Erk mitogen-activated protein kinase and focal adhesion kinase. Urotensin-II-induced proliferation and migration were reproduced in TSC2-deficient human angiomyolipoma cells, but not in those stably expressing TSC2. In a mouse xenograft model, SB657510 blocked the growth of established ELT3 tumors, reduced the number of circulating tumor cells, and attenuated the production of VEGF-D, a clinical biomarker of LAM. Urotensin receptor antagonists may be selective therapeutic agents for the treatment of LAM or other neural crest-derived neoplasms featuring loss of TSC2 or increased expression of the urotensin receptor.

Practical issues in uterine pathology from banal to bewildering: the remarkable spectrum of smooth muscle neoplasia

Among mesenchymal tumors of the uterus, smooth muscle neoplasms are most common. The wide morphologic spectrum, especially within the category of leiomyomas, is responsible for diagnostic problems more frequently with leiomyosarcoma (including mitotically active, apoplectic, and leiomyoma with bizarre nuclei) but also with endometrial stromal tumors. In the former scenario, clinical information, gross appearance as well as strict utilization of morphologic criteria including cytologic atypia, mitotic activity, and tumor cell necrosis are clues in establishing the correct diagnosis. It is important to keep in mind that mitotic rate thresholds vary for the different subtypes of leiomyosarcoma. Of note, p16 should be used with caution in supporting a diagnosis of leiomyosarcoma as it is often positive in leiomyomas with bizarre nuclei and leiomyomas with apoplectic change (in the latter most frequently and more intense near areas of necrosis). MED12 mutations have also a very limited role in this differential diagnosis. Endometrial stromal tumors are by far, less common than smooth muscle tumors, but can be confused with leiomyosarcomas if they are associated with an undifferentiated uterine sarcoma and the low-grade component is overlooked or they have a myxoid/fibroblastic morphology. The differential diagnosis may be confounded if the latter is associated with a high-grade endometrial stromal sarcoma. It is important to highlight that CD10 is not a reliable marker in these differentials and should be used as a part of a panel of antibodies that also includes desmin and h-caldesmon. Two other recently categorized tumors in the uterus that merit special mention are PEComa and inflammatory myofibroblastic tumor as they enter in the differential diagnosis of smooth muscle tumors. PEComa may be part of the tuberous sclerosis syndrome and may show either a predominantly epithelioid or spindle morphology or combination thereof. Rarely, it may contain melanin pigment. There is variable positivity for HMB-45, MelanA, MiTF, and CathepsinK, and some tumors have been shown to express TFE-3 especially when associated with "clear cell" morphology. Patients with adverse outcome have tumors with ≥2 of the following features: ≥5 cm, infiltration, high-grade cytologic features, mitotic rate ≥1/50 high-power fields, necrosis, or lymphovascular invasion. Inflammatory myofibroblastic tumor is important to recognize as it often mimics myxoid smooth muscle tumors, either benign or malignant. The presence of an associated lymphoplasmacytic infiltrate should alert to that possibility and ALK studies (immunostain or FISH) are helpful in establishing this diagnosis. These tumors can behave in a malignant manner if large, associated with abundant myxoid change, brisk mitotic rate or show tumor cell necrosis.

Updates from the Neuro-Oncology Section of the 2015 American Neurological Association Annual Meeting.

American Neurological Association Annual Meeting, Chicago, IL, USA, 27-29 September 2015 The American Neurological Association (ANA) held its annual meeting in Chicago, IL, USA on 27-29 September 2015. The Scientific Programming Advisory Committee was chaired by Dr. S Pleasure from the University of California-San Francisco (CA, USA). The Neuro-Oncology session, chaired by Dr. A Pruitt from the University of Pennsylvania (PA, USA) and cochaired by Dr. J Laterra from Johns Hopkins University (MD, USA), was held on 27 September 2015. Speakers included Dr. D Wainwright (Northwestern University, IL, USA), Dr. N Kolb (University of Utah, UT, USA), Dr. A Nath (NINDS/NIH, MD, USA), Dr. D Franz (Cincinnati Children's Hospital, OH, USA) and Dr. R Lukas (University of Chicago, IL, USA). A summary of key presentations from the Neuro-Oncology section of the 2015 American Neurological Association annual meeting is reported. Preclinical and clinical advances in the use of immunotherapies for the treatment of primary and metastatic CNS tumors are covered. Particular attention is paid to the enzyme indoleamine dioxygenase and the immune checkpoints CTLA4 and PD1 and their ligands. Specific nervous system toxicities associated with novel immunotherapies are also discussed. The recent success of targeting the mTOR pathway in the neurocutaneous syndrome tuberous sclerosis is detailed. Finally, important early steps in our understanding of the common toxicity of chemotherapy induced neuropathy are reviewed.

Treatment of infantile spasms, a Venezuelan experience

We analyzed the treatment of 25 children with infantile spasm, 52% were males and 48% females. Of the cases studied 80% were symptomatic and 20% cryptogenic. Twenty-three children were treated with synthetic adrenocorticotropic hormone (ACTH), in 15 children the ACTH was administered with antiepileptic drugs and two children received vigabatrin. In the symptomatic cases of West syndrome, we found hypoxic-ischemic encephalopathy, tuberous sclerosis, brain malformations and Down syndrome. ACTH was efficacious in symptomatic infantile spasms and in cryptogenic spasms. The side effects most frequently found were: irritability, edema, Cushingoid obesity (moon face), hypertension and hypokalemia. Vigabatrin was used in patients with tuberous sclerosis and was efficacious in the control of infantile spasms. Infantile spasms should be treated as soon as the diagnosis is made. ACTH is still first-choice treatment in patients with West syndrome. The drug of choice of the treatment of infantile spasms in children with tuberous sclerosis is vigabatrin.