TSC1 mutation

We speculate that this new missense variant in TSC2 gene with 30% mosaicism will be associated to the milder phenotype of TS since the regression of the rhabdomyomas is the only manifestation in this patient. We hope that this case report might help clinicians and genetic counselors manage individualized surveillance plans for patients with TS.

Primary renal HB is a rare mesenchymal tumor that requires differentiation from clear cell renal cell carcinoma (CCRCC) using morphological, IHC markers, and genetic testing when necessary. TSC1 could be a specific molecular hallmark of renal HB. Additional case data is required to better understand the molecular genetic alterations of the disease.

We present a frontal lobe intra-axial parenchymal schwannoma containing a CHD7::VGLL3 gene fusion presenting in a 19 month-old male, the youngest patient yet reported for this lesion.

P2, N=18, Active, not recruiting, National Cancer Institute (NCI) | Trial completion date: Oct 2024 --> Oct 2025

This case underscores the efficacy of oral everolimus in reducing FA size in a pediatric TSC patient, with broader therapeutic benefits that support the potential of mTOR inhibition as a multi-targeted strategy for TSC management. Further studies are needed to explore the full range of applications and long-term impact of mTOR inhibitors in TSC care.

Moreover, our analysis showed that some people with TSC1/TSC2 mutations did not match diagnostic criteria. This highlights the importance of genetic testing and molecular profiling in understanding the clinical variability and aiding in the management of TSC patients.

Enfortumab vedotin (EV) is used as monotherapy or combined with pembrolizumab in advanced urothelial carcinoma (aUC), but biomarker data associated with EV outcomes are limited. However, mutations in two genes (CDKN2A and CDKN2B) were associated with worse outcomes after EV treatment. These findings will not affect current clinical practice, but should be investigated further in future studies.

In the second line, we corrected a missense variant in coding exon 40 within the GTPase-activating protein domain (c.5228G>A, p.R1743Q). The generation of TSC2 patient iPSCs in parallel with their corresponding CRISPR-corrected isogenic lines will be an important tool for disease modeling applications and for developing therapeutics.

Of the 8 patients with available follow-up, two died of disease, 3 are currently alive with disease, and 3 have no evidence of disease. The correct recognition of tumors with the KAT6B/A::KANSL1 fusion is essential because despite the bland morphological features of most cases, these tumors have a propensity for aggressive behavior.

Overall, 73% (8/11) tumors with TSC2 IHC loss and underlying pathogenic alterations in TSC2 showed heterogeneous protein loss, with rare interspersed positively staining tumor cells. These data support TSC2 IHC as a potentially useful assay for the diagnostic workup of renal tumors suspected to belong to the TSC/mTOR-associated subgroups.

All patients were alive at last follow up (median follow-up of 85 months). Our report is intended to raise awareness regarding rare instances of metastatic behavior for M/TSC-RCCfms.

P2, N=17, Active, not recruiting, National Cancer Institute (NCI) | N=209 --> 17 | Trial completion date: Jun 2024 --> Nov 2025

P3, N=128, Completed, Marinus Pharmaceuticals | Active, not recruiting --> Completed

This case highlights the potential diagnostic pitfall of SEGA lacking TTF-1 expression and emphasizes the importance of considering this entity in the differential diagnosis of intraventricular tumors, even in the absence of TS and characteristic molecular alterations. The existence of TTF-1 negative SEGAs reveals that these tumors might also derive from TTF-1 negative cells in the subpendymal region.

The tuberous sclerosis complex (TSC1/TSC2/TBC1D7) primarily functions to inhibit the mechanistic target of rapamycin complex 1 (mTORC1), a crucial regulator of cell growth...However, more recent studies have shown that TSC proteins can also promote tumorigenesis in certain cancer types. In this review, we explore the composition and function of the TSC protein complex, the roles of its individual components in cancer biology, and potential future therapeutic targeting strategies.

They are increasingly important as targets for therapeutic intervention such as capivasertib-fulvestrant for HR+HER2- BC with PIK3CA/AKT1/PTEN alterations, or dabrafenib–trametinib for solid tumors with the BRAF V600E mutation. More than half of BC tumor samples had potentially actionable genomic alterations affecting either the PI3K/AKT or MAPK pathways. In HR+HER2- BC, actionable alterations in PIK3CA, AKT1, and PTEN were generally present independently rather than co-occurring. These findings support a comprehensive testing approach that interrogates a large number of genes to maximize the number of patients identified who might benefit from targeted therapies.

HNSCC patients with BM frequently have oropharyngeal primary sites and are HPV+. Common molecular alterations in BM samples, including targetable PIK3CA and ATM, were identified. MAP2K2 alterations were enriched and densities of immune cells were low, highlighting potential targets for further research and immunotherapy considerations.

This finding strengthens the significant phenotypic variability associated with TSC and expands the mutational spectrum of this rare disease.

Notably, similar perturbations were observed in surgically resected cortical specimens from TSC patients. Collectively, our study illustrates that disease-associated TSC2 variants disrupt the neurodevelopmental trajectories through perturbations of gene regulatory networks during early cortical development, leading to mitochondrial dysfunction, aberrant neurofilament formation, impaired synaptic formation and neuronal network activity.

Our data suggest that mTOR activation caused by TSC2 deletion increases PRAS40 expression through miR-142-3p repression. PRAS40 depletion or the pharmacological induction of miR-142-3p expression impaired TSC2 deficiency-associated renal cystogenesis. Therefore, harnessing mTOR/miR-142-3p/PRAS40 signaling cascade may mitigate hyperactivated mTOR-related diseases.

These results suggest the existence of an mTOR oncogenic addiction in biliary tract cancer. Our results support the interest in performing exome sequencing in liver cancers and the potential to identify actionable mutations with important therapeutic issues.

At progression to FGFR inhibitors, FGFR2-driven malignancies are characterized by high intra- and inter-patient molecular heterogeneity, particularly in cholangiocarcinoma. Resistance to FGFR inhibitors can be overcome by sequential, molecularly-oriented treatment strategies across FGFR2-driven tumors.

Our study highlights that morphologic and immunochemical features of CCPRCT may be present in RCCs, including RCC-TFE3 expression and TSC-associated RCC, a critical pitfall to misdiagnose aggressive RCC as indolent CCPRCT and result in undertreatment. Careful examination of morphology and immunostains for CA9, CK7, and TFE3, as well as molecular tests, is crucial for distinguishing aggressive RCC from indolent CCPRCT.

P3, N=128, Active, not recruiting, Marinus Pharmaceuticals | Recruiting --> Active, not recruiting | Trial completion date: Feb 2025 --> Oct 2024 | Trial primary completion date: Jan 2024 --> Oct 2024

Clinicians should be knowledgeable about TSC updated diagnostic criteria. Patients need to be followed up by a multidisciplinary team and treated accordingly. Early detection of cutaneous lesions is important for TSC diagnosis. A significant association between TSC2 gene pathogenic alterations and ungual fibromas is described.

There is little evidence that treatment with MTOR inhibitors, which are beneficial against TSC-mutated PEComas, is effective against TFE3-rearranged PEComas: only one of 6 reported cases demonstrated disease stabilization. As co-expression of melanocytic and muscle markers, a hallmark of conventional TSC-mutated PEComa is uncommon in the spectrum of TFE3-rearranged PEComa, an alternative terminology may be more appropriate, such as "TFE3-rearranged PEComa-like neoplasms," highlighting their distinctive morphologic features and therapeutic implications.

Our research supports the concept that Xanthomatous giant cell renal cell carcinoma (XGC RCC) shares clinicopathological and molecular characteristics with ESC RCC and shows a relatively positive prognosis, providing further support for a close morphologic spectrum between the two. We propose considering XGC RCC as a distinct subtype of ESC RCC.

The mechanistic target of rapamycin (mTOR) pathway serves as a master regulator of cell growth, proliferation, and survival...Advancements in genetic testing, prenatal screening, and precision medicine hold promise for changing the diagnostic and treatment paradigm for TSC and related mTORopathies. Herein, we explore the genetic and molecular mechanisms of TSC and other mTORopathies, emphasizing contemporary genetic methods in understanding and diagnosing the condition.

This molecular finding potentially expands the therapeutic options for patients with renal HB. GPNMB can be considered for inclusion in immunohistochemical panels to improve renal HB identification.

An uncommon molecular finding observed in our case was the presence of TSC1 gene mutation usually associated with soft tissue and gynecological PEComas. Our finding may harbor important therapeutic implications since the inactivation of the tumor suppressor genes TSC1 and TSC2 lead to upregulation of mTOR signaling, providing the rationale for target therapy with mTOR inhibitors. Additional studies on larger series are needed to validate our findings.

There have been very few case reports regarding the presence of PEComa in LFS, and to the best of our knowledge, this is the first report of EAML of the liver in a patient with LFS.

Given that psychiatry may be the first medical contact for TSC patients, especially in low-resource settings, clinicians need to be knowledgeable of various neuropsychiatric conditions and be aware of the possibility of TSC in patients that present with neurocutaneous manifestations. A multidisciplinary team approach is vital for the investigation and management of such cases.

Surprisingly no evidence of any behavioral alterations were found, including the ultrasonic vocalizations of newborns. We decided to focus more attention on the interpretation of data, including a more detailed statistical evaluation of our results.

The TSC of neonatal tuberous sclerosis is different from that of older children. It is usually characterized by respiratory distress and arrhythmia, and may be accompanied by convulsions, but the activity between attacks is normal. However, neonatal intracranial hemorrhage can be caused by premature delivery, birth injury, hypoxia, etc. Its characteristics are acute onset, severe illness, and rapid progression. Consequently, the diagnosis of these 2 diseases should not only be based on medical imaging, but also be combined with their clinical characteristics. When the imaging features are inconsistent with the clinical diagnosis, a comprehensive evaluation should be made again. The timing and pattern of onset of neonatal convulsions can help in differential diagnosis. If there is cardiac rhabdomyoma, subependymal or cortical nodule, skin low melanoma, etc, the possibility of neonatal TSC should be considered, and the diagnosis should be made according to its diagnostic criteria to avoid or reduce misdiagnosis.

In mice, Rapamycin treatment normalizes lysosomal gene expression, similar to TFEB knockout, suggesting that Rapamycin's benefit in TSC is TFEB-dependent. These results change the view of the mechanisms of mTORC1 hyperactivation in TSC and may lead to therapeutic avenues.

TP53 and TSC1 co-mutations were identified as detrimental factors affecting efficacy. This study provides references for the response to alectinib in patients with different types of ALK rearrangements and co-mutation.

The review is narrative in nature, without any date restrictions, and summarizes the most relevant literature on the neurological aspects and management of TSC. By consolidating the current understanding of TSC neurobiology and evidence-based treatment strategies, this review provides an invaluable reference that highlights progress made while also emphasizing areas requiring further research to optimize care and outcomes for TSC patients.

Lymphangioleiomyomatosis (LAM) is a progressive cystic lung disease caused by tuberous sclerosis complex 1/2 (TSC1/2) gene mutations in pulmonary mesenchymal cells resulting in activation of the mechanistic target of rapamycin complex 1 (mTORC1)...The proposed pathophysiologic mesenchymal ligand/ EC receptor crosstalk highlights the importance of an altered mesenchymal-EC axis in LAM and other hyperactive mTORC1-driven diseases. Since ECs in LAM patients and in Tbx4LME-CreTsc2fl/fl mice do not harbor TSC2 mutations, our study demonstrates that constitutively active mTORC1 lung mesenchymal cells orchestrate dysfunctional EC responses which contribute to pulmonary vascular remodeling.

Inactivating TSC1 and/or TSC2 alterations commonly occurred in GU cancers. A proportion of GU tumors have a low TMB and/or are microsatellite stable, suggesting that TSC1 and TSC2 inactivating alterations may be driver mutations rather than passenger mutations in those tumors. Therefore, patients with inactivating alterations in TSC1 or TSC2 may benefit from mTOR inhibition via nab-sirolimus.

Cardiac rhabdomyoma is a rare fetal and pediatric pathology that generally is a remarkable finding in the clinical process of TSC. Therefore, cases should be evaluated multisystemically and genetic counseling should be given to the family.

In exploratory biomarker analyses of patients with perivascular epithelioid cell tumors treated with the mTOR inhibitor nab-sirolimus (AMPECT, NCT02494570), those with inactivating alterations in the tumor suppressor genes TSC1 or TSC2 (critical negative regulators of mTOR activity) had confirmed responses (8/9 patients with inactivating TSC2 alterations and 1/5 patients with inactivating TSC1 alterations)...TSC1 and/or TSC2 alterations were commonly observed in GI cancers. These cancers were frequently microsatellite stable and of low TMB suggesting that these are actionable alterations that may be candidates for targeted therapy. This hypothesis is being tested in the PRECISION 1 (NCT05103358) trial which is open for enrollment or just-in-time clinical trial sites and available to patients with GI cancers harboring TSC1 or TSC2 alterations.

TSC1 and TSC2 code for the proteins harmartin and tuberin, respectively, which form a complex that regulates the mechanistic target of rapamycin complex 1 (mTORC1) and prevents uncontrollable cell growth...These results unequivocally demonstrate the critical role that FOXI1 and A-IC cells, along with H-ATPase, play in TSC kidney cystogenesis. This review article will discuss the latest research into the causes of kidney cystogenesis in TSC with a focus on possible therapeutic options for this devastating disease.