Everolimus (RAD001): first systemic treatment for subependymal giant cell astrocytoma associated with tuberous sclerosis complex

Bridging the age gap: a review of molecularly informed treatments for glioma in adolescents and young adults

Gliomas are the most common primary central nervous system (CNS) tumors and a major cause of cancer-related mortality in children (age <15 years), adolescents and young adults (AYA, ages 15-39 years), and adults (age >39 years). Molecular pathology has helped enhance the characterization of these tumors, revealing a heterogeneous and ever more complex group of malignancies. Recent molecular analyses have led to an increased appreciation of common genomic alterations prevalent across all ages. The 2021 World Health Organization (WHO) CNS tumor classification, 5th edition (WHO CNS5) brings forward a nomenclature distinguishing "pediatric-type" and "adult-type" gliomas. The spectrum of gliomas in AYA comprises both "pediatric-like" and "adult-like" tumor entities but remains ill-defined. With fragmentation of clinical management between pediatric and adult centers, AYAs face challenges related to gaps in medical care, lower rates of enrollment in clinical trials and additional psychosocial and economic challenges. This calls for a rethinking of diagnostic and therapeutic approaches, to improve access to appropriate testing and potentially beneficial treatments to patients of all ages.

Rapamycin and rapalogs for tuberous sclerosis complex

BACKGROUND

Potential benefits of rapamycin or rapalogs for treating people with tuberous sclerosis complex (TSC) have been shown. Currently everolimus (a rapalog) is only approved for TSC-associated renal angiomyolipoma and subependymal giant cell astrocytoma (SEGA), but not other manifestations of TSC. A systematic review needs to establish evidence for rapamycin or rapalogs for various manifestations in TSC. This is an updated review.

OBJECTIVES

To determine the effectiveness of rapamycin or rapalogs in people with TSC for decreasing tumour size and other manifestations and to assess the safety of rapamycin or rapalogs in relation to their adverse effects.

SEARCH METHODS

We identified relevant studies from the Cochrane-Central-Register-of-Controlled-Trials (CENTRAL), Ovid MEDLINE and ongoing trials registries with no language restrictions. We searched conference proceedings and abstract books of conferences. Date of the last searches: 15 July 2022.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs of rapamycin or rapalogs in people with TSC.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the risk of bias of each study; a third review author verified the extracted data and risk of bias decisions. We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

The current update added seven RCTs, bringing the total number to 10 RCTs (with 1008 participants aged 3 months to 65 years; 484 males). All TSC diagnoses were by consensus criteria as a minimum. In parallel studies, 645 participants received active interventions and 340 placebo. Evidence is low-to-high certainty and study quality is mixed; mostly a low risk of bias across domains, but one study had a high risk of performance bias (lack of blinding) and three studies had a high risk of attrition bias. Manufacturers of the investigational products supported eight studies. Systemic administration Six studies (703 participants) administered everolimus (rapalog) orally. More participants in the intervention arm reduced renal angiomyolipoma size by 50% (risk ratio (RR) 24.69, 95% confidence interval (CI) 3.51 to 173.41; P = 0.001; 2 studies, 162 participants, high-certainty evidence). In the intervention arm, more participants in the intervention arm reduced SEGA tumour size by 50% (RR 27.85, 95% CI 1.74 to 444.82; P = 0.02; 1 study; 117 participants; moderate-certainty evidence) ,and reported more skin responses (RR 5.78, 95% CI 2.30 to 14.52; P = 0.0002; 2 studies; 224 participants; high-certainty evidence). In one 18-week study (366 participants), the intervention led to 25% fewer seizures (RR 1.63, 95% CI 1.27 to 2.09; P = 0.0001) or 50% fewer seizures (RR 2.28, 95% CI 1.44 to 3.60; P = 0.0004); but there was no difference in numbers being seizure-free (RR 5.30, 95% CI 0.69 to 40.57; P = 0.11) (moderate-certainty evidence). One study (42 participants) showed no difference in neurocognitive, neuropsychiatry, behavioural, sensory and motor development (low-certainty evidence). Total adverse events (AEs) did not differ between groups (RR 1.09, 95% CI 0.97 to 1.22; P = 0.16; 5 studies; 680 participants; high-certainty evidence). However, the intervention group experienced more AEs resulting in withdrawal, interruption of treatment, or reduced dose (RR 2.61, 95% CI 1.58 to 4.33; P = 0.0002; 4 studies; 633 participants; high-certainty evidence and also reported more severe AEs (RR 2.35, 95% CI 0.99 to 5.58; P = 0.05; 2 studies; 413 participants; high-certainty evidence). Topical (skin) administration Four studies (305 participants) administered rapamycin topically. More participants in the intervention arm showed a response to skin lesions (RR 2.72, 95% CI 1.76 to 4.18; P < 0.00001; 2 studies; 187 participants; high-certainty evidence) and more participants in the placebo arm reported a deterioration of skin lesions (RR 0.27, 95% CI 0.15 to 0.49; 1 study; 164 participants; high-certainty evidence). More participants in the intervention arm responded to facial angiofibroma at one to three months (RR 28.74, 95% CI 1.78 to 463.19; P = 0.02) and three to six months (RR 39.39, 95% CI 2.48 to 626.00; P = 0.009; low-certainty evidence). Similar results were noted for cephalic plaques at one to three months (RR 10.93, 95% CI 0.64 to 186.08; P = 0.10) and three to six months (RR 7.38, 95% CI 1.01 to 53.83; P = 0.05; low-certainty evidence). More participants on placebo showed a deterioration of skin lesions (RR 0.27, 95% CI 0.15 to 0.49; P < 0.0001; 1 study; 164 participants; moderate-certainty evidence). The intervention arm reported a higher general improvement score (MD -1.01, 95% CI -1.68 to -0.34; P < 0.0001), but no difference specifically in the adult subgroup (MD -0.75, 95% CI -1.58 to 0.08; P = 0.08; 1 study; 36 participants; moderate-certainty evidence). Participants in the intervention arm reported higher satisfaction than with placebo (MD -0.92, 95% CI -1.79 to -0.05; P = 0.04; 1 study; 36 participants; low-certainty evidence), although again with no difference among adults (MD -0.25, 95% CI -1.52 to 1.02; P = 0.70; 1 study; 18 participants; low-certainty evidence). Groups did not differ in change in quality of life at six months (MD 0.30, 95% CI -1.01 to 1.61; P = 0.65; 1 study; 62 participants; low-certainty evidence). Treatment led to a higher risk of any AE compared to placebo (RR 1.72, 95% CI 1.10, 2.67; P = 0.02; 3 studies; 277 participants; moderate-certainty evidence); but no difference between groups in severe AEs (RR 0.78, 95% CI 0.19 to 3.15; P = 0.73; 1 study; 179 participants; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

Oral everolimus reduces the size of SEGA and renal angiomyolipoma by 50%, reduces seizure frequency by 25% and 50% and implements beneficial effects on skin lesions with no difference in the total number of AEs compared to placebo; however, more participants in the treatment group required a dose reduction, interruption or withdrawal and marginally more experienced serious AEs compared to placebo. Topical rapamycin increases the response to skin lesions and facial angiofibroma, an improvement score, satisfaction and the risk of any AE, but not severe adverse events. With caution regarding the risk of severe AEs, this review supports oral everolimus for renal angiomyolipoma, SEGA, seizure, and skin lesions, and topical rapamycin for facial angiofibroma.

Use and outcomes of kidneys from donors with renal angiomyolipoma: A systematic review

BACKGROUND

Renal angiomyolipoma (AML) is the most frequent mesenchymal tumor of the kidney. Although there is a rare possibility of malignant transformation of AML, this risk has not been studied in immunosuppressed patients. The safety of donors with AML and their kidney transplant recipients has not been well established.

METHODS

A literature search was conducted utilizing MEDLINE, EMBASE, and Cochrane databases from inception through May 15, 2018 (updated on October 2019). We included studies that reported the outcomes of kidney donors with AML or recipients of donor with AML. The protocol for this meta-analysis is registered with PROSPERO (International Prospective Register of Systematic Reviews; no. CRD42018095157).

RESULTS

Fourteen studies with a total of 16 donors with AML were identified. None of the donors had a diagnosis of tuberous sclerosis complex (TSC), pulmonary lymphangioleiomyomatosis (LAM), or epithelioid variant of AML. Donor age ranged from 35 to 77 years, and recipient age ranged from 27 to 62 years. Ninety-two percent of the donors were female. Only 8% were deceased donor renal transplant. The majority underwent ex vivo resection (65%) before transplantation, followed by no resection (18%), and the remaining had in vivo resection. Tumor size varied from 0.4 cm to 7 cm, and the majority (87%) were localized in the right kidney. Follow-up time ranged from 1 to 107 months. Donor creatinine prenephrectomy ranged 0.89-1.1 mg/dL and postnephrectomy creatinine 1.0-1.17 mg/dL. In those who did not have resection of the AML, tumor size remained stable. None of the donors with AML had end-stage renal disease or died at last follow-up. None of the recipients had malignant transformation of AML.

CONCLUSION

These findings are reassuring for the safety of donors with AML (without TSC or LAM) as well as their recipients without evidence of malignant transformation of AML. As such, this can also positively impact the donor pool by increasing the number of available kidneys.

Everolimus dosing recommendations for tuberous sclerosis complex-associated refractory seizures

Objective

The present analysis examined the exposure‐response relationship by means of the predose everolimus concentration (C_min) and the seizure response in patients with tuberous sclerosis complex–associated seizures in the EXIST‐3 study. Recommendations have been made for the target C_min range of everolimus for therapeutic drug monitoring (TDM) and the doses necessary to achieve this target C_min.

Methods

A model‐based approach was used to predict patients' daily C_min. Time‐normalized C_min (TN‐C_min) was calculated as the average predicted C_min in a time interval. TN‐C_min was used to link exposure to efficacy and safety end points via model‐based approaches. A conditional logistic regression stratified by age subgroup was used to estimate the probability of response in relation to exposure. A multiplicative linear regression model was used to estimate the exposure‐response relationship for seizure frequency (SF). An extended Cox regression model was used to link exposure to the time to first adverse event.

Results

There was a strong, consistent, and highly significant relationship between everolimus exposure and efficacy, measured by TN‐C_min and SF, regardless of patient's age and concomitant use of cytochrome P450 3A4 (CYP3A4) inhibitors/inducers. Results of an extended Cox regression analyses indicated that twofold increases in TN‐C_min were not associated with statistically significant increases in the risk of stomatitis or infections.

Significance

The recommended TDM is to target everolimus C_min within a range of 5‐7 ng/mL initially and 5‐15 ng/mL in the event of an inadequate clinical response, and safety is consistent with previous reports. Starting doses depend on age and the concomitant use of CYP3A4/P‐glycoprotein inducers/inhibitors.

Papillary thyroid carcinoma in a boy with familial tuberous sclerosis complex attributable to a TSC2 deletion-a case report

Tuberous sclerosis complex (tsc), a phacomatosis, is a rare genetic disease (autosomal dominant; incidence: 1 in 6,800-17,300) associated with mutations in the TSC1 and TSC2 genes, 70% of which are sporadic. The disease causes benign tumours in the brain, kidneys, heart, lungs, skin, and eyes; thyroid lesions are extremely rare. A 13-year-old euthyroid boy with a hereditary form of tsc (del 4730G in TSC2, also seen in 2 sisters and the father) was admitted to hospital with a thyroid nodule. Physical examination revealed a nodular left lobe with increased consistency. Thyroid ultrasonography revealed a heterogeneous left lobe, predominantly hypoechoic with multiple microcalcifications and the presence of suspicious cervical lymph nodes on the left side. A macrocalcification was observed on the right lobe. Fine-needle biopsy results showed a few groups of cells with discrete atypical characteristics, including abundant cytoplasm, nuclei with conspicuous nucleoli, intra-nuclear inclusions, and nuclear grooves. The patient underwent total thyroidectomy with lymphadenectomy. Histopathology examination confirmed papillary thyroid carcinoma. The coincidence of endocrine neoplasia including thyroid cancer and tsc is rare, and tsc with papillary thyroid carcinoma has never been described in a child. Studies of mutations in the tumour suppressor genes TSC1, TSC2, and STK11, activating the mtor (mammalian target of rapamycin) pathway, might support their role in the pathogenesis of thyroid cancer.

Treatment of Renal Angiomyolipoma and Other Hamartomas in Patients with Tuberous Sclerosis Complex

Tuberous sclerosis complex is an autosomal dominant genetic disease characterized by growth of benign tumors (hamartomas) in multiple organs, especially the kidneys, brain, heart, lungs, and skin. Tuberous sclerosis complex is usually caused by a mutation in either the tuberous sclerosis complex 1 or tuberous sclerosis complex 2 gene, resulting in constitutive activation of mammalian target of rapamycin signaling. Currently, mammalian target of rapamycin inhibitors are recommended in adult patients with tuberous sclerosis complex for the treatment of asymptomatic, growing renal angiomyolipoma that are >3 cm in diameter and pediatric or adult patients with brain lesions (subependymal giant cell astrocytoma) that either are growing or are not amenable to surgical resection. Clinical evidence suggests that systemic administration of a mammalian target of rapamycin inhibitor may provide concurrent improvements in multiple lesions and symptoms of tuberous sclerosis complex. With the major paradigm shift in consensus guidelines toward screening at diagnosis and ongoing monitoring and with the recent availability of an effective oral treatment, it is important that nephrologists have a thorough understanding of our role in the management of patients with tuberous sclerosis complex. Because the various manifestations of tuberous sclerosis complex typically emerge at different periods during patients' lifetimes, patients will need to be followed throughout their lives. Unlike brain and cardiac lesions, renal lesions are more likely to emerge as patients age and can grow at any time. Considerations regarding long-term medication administration for the potential control of multiple tuberous sclerosis complex manifestations will need to be addressed; these include the most appropriate starting dose, appropriate doses for tumor shrinkage versus prevention of regrowth, and management of adverse events. Best practices and potential obstacles for nephrologists treating patients with tuberous sclerosis complex who have multiple manifestations are considered.

Accelerated Cardiac Rhabdomyoma Regression with Everolimus in Infants with Tuberous Sclerosis Complex

Tuberous sclerosis complex is associated with benign tumors such as cardiac rhabdomyomas (RHM) caused by the disinhibition of the mammalian target of rapamycin (mTOR) protein. Recent reports on everolimus, an mTOR inhibitor, have shown size reduction of RHM. We compared cases recently treated with everolimus to historic controls whose first echocardiography was within first month of life. The largest dimension of the largest RHM was reported as a percentage compared to the earliest echocardiography study. Treatment of the four cases was started at a median age of 6.5 days (range 2-20) with an initial enteral dose of 0.1 mg daily, aiming at a therapeutic serum trough level of 5-15 ng/mL. Median duration of everolimus treatment was 73 days (range 34-138). Compared to 10 historic controls, everolimus-treated patients had 11.8 times faster RHM size regression rate (slope -0.0285 vs. -0.0024; p < 0.001). The average time to 50% size reduction was 1.13 ± 0.33 month (range 0.66-1.4 months) with everolimus versus 72.9 ± 53.03 months in controls (p = 0.026). Following treatment with everolimus, one case was operated for congenital heart disease, without requirement of RHM resection, two others had the massive left ventricle RHM shrink to non-consequential size. The latter had a disappearance of RHM, but everolimus therapy was maintained to prevent the regrowth of a significant cerebral tumor. Everolimus is efficacious for size reduction of RHM during the neonatal period. With limited safety data, this approach should be used with caution in selective cases.

Mammalian Target of Rapamycin Inhibitor Induced Complete Remission of a Recurrent Subependymal Giant Cell Astrocytoma in a Patient Without Features of Tuberous Sclerosis Complex

The majority of patients with subependymal giant cell astrocytoma (SEGA) have tuberous sclerosis complex (TSC). In such patients, the mammalian target of rapamycin (mTOR) inhibitor everolimus has been shown to induce responses. Isolated SEGA have been reported in patients without clinical or genetic features of TSC. The treatment of these patients with everolimus has not previously been reported. We treated a patient with a recurrent isolated SEGA with an mTOR inhibitor. The patient tolerated therapy well and had a sustained complete remission. MTOR inhibitors may be useful for the treatment of isolated SEGA. Further study is warranted.

Natural History and Current Treatment Options for Subependymal Giant Cell Astrocytoma in Tuberous Sclerosis Complex

Subependymal giant cell astrocytoma (SEGA) is a benign brain tumor associated with tuberous sclerosis complex (TSC). Since there were some discrepancies in SEGA classification, in 2012, a consensus statement defined SEGA as a lesion at the caudothalamic groove with either a size of more than 1cm in any direction or a subependymal lesion at any location that has shown serial growth on consecutive imaging regardless of size. This pointed that the documented tumor growing is an important diagnostic feature. Currently, there are 2 therapeutic options: surgical and medical with mammalian target of rapamycin (mTOR) inhibitors. Neurosurgery should consider a localization and size of the tumor, presence of hydrocephalus and surgeon's experience. Patients who are not qualified for surgery and require therapeutic intervention are subjected to mTOR inhibitors therapy. Everolimus, one of the mTOR inhibitors, has been recently approved in the US and Europe for treatment of patients with TSC and SEGA. Treatment with everolimus results in a rapid initial reduction in tumor volume, followed by a phase of slower reduction or stabilization of residual mass. mTOR inhibitor dose de-escalation strategy seems to be also logical in long-term SEGA treatment to reduce the risk of adverse effects while maintaining the therapeutic effect. However, duration of the treatment and the efficacy of dose reduction are still questionable. Thus, this review covers the various approaches that are currently being made toward improving the outcome of management of SEGA among patients with TSC.

Long-Term Everolimus Treatment in Individuals With Tuberous Sclerosis Complex: A Review of the Current Literature

BACKGROUND

Tuberous sclerosis complex is a genetic disease usually caused by mutations to either TSC1 or TSC2, where its gene products are involved in the inhibition of the mammalian target of rapamycin pathway. Under normal cellular conditions, mammalian target of rapamycin (mTOR) regulates cell growth and proliferation in response to signals from nutrients or growth factors, but loss of TSC1 or TSC2 leads to overactivation of mTOR and uncontrolled cellular proliferation. Everolimus is an mTOR inhibitor approved for use in a number of indications where mTOR overactivation is implicated, including tuberous sclerosis complex.

METHODS AND PATIENTS

We conducted a literature search of PubMed to identify published articles about the long-term efficacy and safety of everolimus in patients with tuberous sclerosis complex.

RESULTS

The short-term efficacy and safety of everolimus in patients with tuberous sclerosis complex has been demonstrated in placebo-controlled trials, and open-label extension studies are ongoing to monitor long-term effects, including safety. Examples of regrowth following discontinuation of mTOR inhibitors suggest that everolimus needs to be given indefinitely to maintain suppression of subependymal giant cell astrocytoma and other tuberous sclerosis complex-associated disease manifestations. No additional safety concerns have been reported to date with long-term administration of everolimus, but published long-term data (>1 year treatment) are currently limited to a small open-label trial and case reports for this relatively rare condition.

CONCLUSIONS

From the limited data available, long-term administration of everolimus appears feasible with few safety concerns beyond those associated with short-term use. Further investigation is needed to determine the long-term efficacy and safety of everolimus in patients with tuberous sclerosis complex.

Infantile tauopathies: Hemimegalencephaly; tuberous sclerosis complex; focal cortical dysplasia 2; ganglioglioma

Tau is a normal microtubule-associated protein; mutations to phosphorylated or acetylated forms are neurotoxic. In many dementias of adult life tauopathies cause neuronal degeneration. Four developmental disorders of the fetal and infant brain are presented, each of which exhibits up-regulation of tau. Microtubules are cytoskeletal structures that provide the strands of mitotic spindles and specify cellular polarity, growth, lineage, differentiation, migration and axonal transport of molecules. Phosphorylated tau is abnormal in immature as in mature neurons. Several malformations are demonstrated in which upregulated tau may be important in pathogenesis. All produce highly epileptogenic cortical foci. The prototype infantile tauopathy is (1) hemimegalencephaly (HME); normal tau is degraded by a mutant AKT3 or AKT1 gene as the aetiology of focal somatic mosaicism in the periventricular neuroepithelium. HME may be isolated or associated with neurocutaneous syndromes, particularly epidermal naevus syndromes, also due to somatic mutations. Other tauopathies of early life include: (2) tuberous sclerosis complex; (3) focal cortical dysplasia type 2b (FCD2b); and (4) ganglioglioma, a tumor with dysplastic neurons and neoplastic glial cells. Pathological tau in these infantile cases alters cellular growth and architecture, synaptic function and tissue organization, but does not cause neuronal loss. All infantile tauopathies are defined neuropathologically as a tetrad of (1) dysmorphic and megalocytic neurons; (2) activation of the mTOR signaling pathway; (3) post-zygotic somatic mosaicism; and (4) upregulation of phosphorylated tau. HME and FCD2b may be the same disorder with different timing of the somatic mutation in the mitotic cycles of the neuroepithelium. HME and FCD2b may be the same disorder with different timing of the somatic mutation in the mitotic cycles of the neuroepithelium. Tauopathies must be considered in infantile neurological disease and no longer restricted to adult dementias. The mTOR inhibitor everolimus, already demonstrated to be effective in TSC, also may be a potential treatment in other infantile tauopathies.

Use of mTOR inhibitor everolimus in three neonates for treatment of tumors associated with tuberous sclerosis complex

BACKGROUND

Tuberous sclerosis complex is characterized by the growth of benign tumors in multiple organs, caused by the disinhibition of the mammalian target of rapamycin (mTOR) protein. mTOR inhibitors, such as everolimus, are used in patients with tuberous sclerosis complex, mainly to reduce the size of renal angiomyolipomas and subependymal giant cell astrocytomas. There are minimal data available regarding its use during the neonatal period.

METHODS

We report clinical and pharmacological data of three neonates treated with the mTOR inhibitor everolimus (two hemodynamically significant cardiac rhabdomyomas and one voluminous subependymal giant cell astrocytoma).

RESULTS

Beneficial clinical responses were observed in all three patients and the medication was generally well-tolerated. Optimal dose was 0.1 mg orally once daily and was confirmed with therapeutic drug monitoring.

CONCLUSION

Everolimus is a promising pharmacological approach to treat clinically significant inoperable cardiac rhabdomyomas or subependymal giant cell astrocytoma associated with tuberous sclerosis complex during the neonatal period.

Epilepsy in newborns with tuberous sclerosis complex

BACKGROUND

Epilepsy affects up to 90% of TSC patients and majority of them have seizure at the age of 3-5 months, after a period of latent epileptogenesis, but some develop epilepsy earlier.

AIMS

The aim of this work was to identify incidence, clinical characteristics, and risk factors for neonatal onset of epilepsy in a large cohort of TSC patients.

METHODS

A retrospective review of medical data of 421 TSC patients was performed. Patients who developed epilepsy within first 4 weeks of life were included in the study. Clinical and treatment data, EEG, MRI, and genetic analyses were assessed.

RESULTS

Epilepsy was present in 366 (86.9%) patients. Twenty-one (5.7%) developed epilepsy as newborns. Mean follow-up was 44.86 (6-170) months. Six patients were seizure free and 15 had drug-resistant seizures at the end of follow-up. Mental retardation was found in 81% of patients. In 11 (52.4%) patients brain MRI revealed large malformations of cerebral cortex, meeting the criteria for focal cortical dysplasia (FCD). FCD was revealed in both TSC1 and TSC2 mutation cases. Other risk factors for neonatal epilepsy included: perinatal complications and congenital SEGAs. Presence of FCD was associated with more severe epilepsy and worse neuropsychological outcome. Epilepsy surgery resulted in improvement in seizure control.

CONCLUSIONS

Neonatal onset of epilepsy in TSC is frequently associated with large malformations of cerebral cortex. Patients with FCD are at high risk of severe drug-resistant epilepsy and poor neuropsychological outcome. Early epilepsy surgery may be beneficial and should be considered in such cases.

Tailoring mTOR-based therapy: molecular evidence and clinical challenges

The mTOR signaling pathway integrates inputs from a variety of upstream stimuli to regulate diverse cellular processes including proliferation, growth, survival, motility, autophagy, protein synthesis and metabolism. The mTOR pathway is dysregulated in a number of human pathologies including cancer, diabetes, obesity, autoimmune disorders, neurological disease and aging. Ongoing clinical trials testing mTOR-targeted treatments number in the hundreds and underscore its therapeutic potential. To date mTOR inhibitors are clinically approved to prevent organ rejection, to inhibit restenosis after angioplasty, and to treat several advanced cancers. In this review we discuss the continuously evolving field of mTOR pharmacogenomics, as well as highlight the emerging efforts in identifying diagnostic and prognostic markers, including miRNAs, in order to assess successful therapeutic responses.

Realizing the promise of cancer predisposition genes

Genes in which germline mutations confer highly or moderately increased risks of cancer are called cancer predisposition genes. More than 100 of these genes have been identified, providing important scientific insights in many areas, particularly the mechanisms of cancer causation. Moreover, clinical utilization of cancer predisposition genes has had a substantial impact on diagnosis, optimized management and prevention of cancer. The recent transformative advances in DNA sequencing hold the promise of many more cancer predisposition gene discoveries, and greater and broader clinical applications. However, there is also considerable potential for incorrect inferences and inappropriate clinical applications. Realizing the promise of cancer predisposition genes for science and medicine will thus require careful navigation.

Objective monitoring of mTOR inhibitor therapy by three-dimensional facial analysis

With advances in therapeutics for rare, genetic and syndromic diseases, there is an increasing need for objective assessments of phenotypic endpoints. These assessments will preferentially be high precision, non-invasive, non-irradiating, and relatively inexpensive and portable. We report a case of a child with an extensive lymphatic vascular malformation of the head and neck, treated with an mammalian target of Rapamycin (mTOR) inhibitor that was assessed using 3D facial analysis. This case illustrates that this technology is prospectively a cost-effective modality for treatment monitoring, and it supports that it may also be used for novel explorations of disease biology for conditions associated with disturbances in the mTOR, and interrelated, pathways.

Possible prevention of tuberous sclerosis complex lesions

Tuberous sclerosis complex (TSC) is a genetic disorder characterized by mammalian target of rapamycin (mTOR) activation and growth of benign tumors. Some TSC lesions, such as cardiac rhabdomyomas and cortical tubers in the brain, occur in fetuses, and some, such as renal angiomyolipomas (AMLs) and skin angiofibromas, develop over years. Recently, the mTOR inhibitor everolimus was shown to be effective in the treatment of subependymal giant cell astrocytomas (a brain tumor) and renal AMLs (kidney tumors) in TSC patients. We present monozygotic twin sisters affected with TSC. Since age 4 years, 1 of the sisters has been treated with everolimus; the other sister received no mTOR inhibitor treatment. After 24-month follow-up, everolimus treatment resulted in a significant brain tumor volume decrease in the treated twin. This child presents no facial angiofibroma, and no renal AMLs. The brain tumor in the nontreated sister is stable in size, but in the meantime, she has developed significant facial angiofibroma and renal AMLs. This observation indicates that early mTOR inhibition in TSC patients may prevent the development of TSC lesions and alter the natural history of the disease.

Learning from the Cardiologists and Developing Eluting Stents Targeting the Mtor Pathway for Pulmonary Application; A Future Concept for Tracheal Stenosis

Tracheal stenosis due to either benign or malignant disease is a situation that the pulmonary physicians and thoracic surgeons have to cope in their everyday clinical practice. In the case where tracheal stenosis is caused due to malignancy mini-interventional interventions with laser, apc, cryoprobe, balloon dilation or with combination of more than one equipment and technique can be used. On the other hand, in the case of a benign disease such as; tracheomalacia the clinician can immediately upon diagnosis proceed to the stent placement. In both situations however; it has been observed that the stents induce formation of granuloma tissue in both or one end of the stent. Therefore a frequent evaluation of the patient is necessary, taking also into account the nature of the primary disease. Evaluation methodologies identifying different types and extent of the trachea stenosis have been previously published. However; we still do not have an effective adjuvant therapy to prevent granuloma tissue formation or prolong already treated granuloma lesions. There have been proposed many mechanisms which induce the abnormal growth of the local tissue, such as; local pressure, local stress, inflammation and vascular endothelial growth factor overexpression. Immunomodulatory agents inhibiting the mTOR pathway are capable of inhibiting the inflammatory cascade locally. In the current mini-review we will try to present the current knowledge of drug eluting stents inhibiting the mTOR pathway and propose a future application of these stents as a local anti-proliferative treatment.