Hamartoma

Tuberous Sclerosis Complex (TSC) is caused by TSC1 or TSC2 mutations, leading to hyperactivation of mechanistic target of rapamycin complex 1 (mTORC1) and lesions in multiple organs including lung (lymphangioleiomyomatosis) and kidney (angiomyolipoma and renal cell carcinoma). Previously, we found that TFEB is constitutively active in TSC. Here, we generated two mouse models of TSC in which kidney pathology is the primary phenotype. Knockout of TFEB rescues kidney pathology and overall survival, indicating that TFEB is the primary driver of renal disease in TSC. Importantly, increased mTORC1 activity in the TSC2 knockout kidneys is normalized by TFEB knockout. In TSC2-deficient cells, Rheb knockdown or Rapamycin treatment paradoxically increases TFEB phosphorylation at the mTORC1-sites and relocalizes TFEB from nucleus to cytoplasm. 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.

BackgroundTuberous sclerosis complex (TSC) is associated with a wide range of physical manifestations for which international clinical recommendations for diagnosis and management have been established. TSC is, however, also associated with a wide range of TSC-Associated Neuropsychiatric Disorders (TAND) that are typically under-identified and under-treated yet associated with a profound burden of disease. The contemporary evidence base for the identification and treatment of TAND is much more limited and, to date, consensus recommendations for the diagnosis and management of TAND have also been limited and non-specific.MethodsThe TANDem project was launched with an international, interdisciplinary, and participatory consortium of 24 individuals, including TSC family representatives, from all World Health Organization (WHO) regions but one. One of the aims of the TANDem project was to generate consensus recommendations for the identification and treatment of TAND. At the time of this project, no internationally adopted standard methodology and methodological checklists existed for the generation of clinical practice recommendations. We therefore developed our own systematic procedure for evidence review and consensus-building to generate evidence-informed consensus recommendations of relevance to the global TSC community.ResultsAt the heart of the consensus recommendations are ten core principles surrounded by cluster-specific recommendations for each of the seven natural TAND clusters identified in the literature (autism-like, dysregulated behavior, eat/sleep, mood/anxiety, neuropsychological, overactive/impulsive, and scholastic) and a set of wraparound psychosocial cluster recommendations. The overarching recommendation is to "screen" for TAND at least annually, to "act" using appropriate next steps for evaluation and treatment, and to "repeat" the process to ensure early identification and early intervention with the most appropriate biological, psychological, and social evidence-informed approaches to support individuals with TSC and their families.ConclusionsThe consensus recommendations should provide a systematic framework to approach the identification and treatment of TAND for health, educational, social care teams and families who live with TSC. To ensure global dissemination and implementation of these recommendations, partnerships with the international TSC community will be important. One of these steps will include the generation of a "TAND toolkit" of "what to seek" and "what to do" when difficulties are identified in TAND clusters.

ImportanceIdentifying hereditary cancer predisposition facilitates high-risk organ-specific cancer surveillance and prevention. In PTEN hamartoma tumor syndrome (PHTS), longitudinal studies remain lacking, and there are insufficient data on cancers in children and young adults, as well as individuals with neurodevelopmental disorders (NDD).ObjectiveTo evaluate lifetime cancer risks, including second malignant neoplasms (SMN), among patients with PHTS.Design, setting, and participantsProspective longitudinal cohort study (September 1, 2005, through January 6, 2022). General population risks from the Surveillance, Epidemiology, and End Results database. Patients with PHTS, molecularly defined as carrying germline PTEN variants, were accrued from community and academic medical centers throughout North America, South America, Europe, Australia, and Asia. Data were analyzed from July 2022 to February 2023.ExposuresReview of physical and electronic medical records, and follow-up through clinical visits or telephone interviews.Main outcomes and measuresLifetime cancer risks in PHTS relative to the general population.ResultsA total of 7302 patients were prospectively accrued, 701 of whom had germline PTEN variants (median [IQR] age at consent, 38 [12-52] years; 413 female patients [59%]). Longitudinal follow-up data could be obtained for 260 patients (37%), with a median (IQR) follow-up of 4 (2-8) years. Of the 701 patients, 341 (49%) received at least 1 cancer diagnosis, with 144 (42%) of those having SMN. The study found significantly elevated lifetime risks for breast (91%), endometrial (48%), thyroid (33%), kidney (30%), and colorectal cancers (17%), as well as melanoma (5%). Cancer diagnoses were also observed in children and young adults with PHTS (15%) and in patients with PHTS with neurodevelopmental disorders (11%). Elevated risks (P Conclusions and relevanceThis cohort study found consistently elevated lifetime cancer risks in PHTS. Organ-specific surveillance should continue in patients with PHTS. Additional study is required to ascertain elevated cancer risks in patients with PHTS with NDD.

PTEN hamartoma tumour syndrome (PHTS), a rare disease caused by germline heterozygous PTEN variants, is associated with multi-organ/tissue overgrowth, autism spectrum disorder and increased cancer risk. Phenotypic variability in PHTS is partly due to diverse PTEN variants and the protein's multifaceted functions. PTEN is primarily a phosphatidylinositol(3,4,5)trisphosphate (PIP3) phosphatase regulating PI3K/AKT signalling but also maintains chromosomal stability through nuclear functions such as double-stranded (ds)DNA damage repair. Here, we show that PTEN-R173C, a pathogenic variant frequently found in PHTS and somatic cancer, has elevated PIP3 phosphatase activity that effectively regulates canonical PI3K/AKT signalling. However, PTEN-R173C is unstable and excluded from the nucleus. We generated Pten+/R173C mice which developed few tumours during their lifetime, aligning with normal PI3K/AKT signalling. However, they exhibited lymphoid hyperplasia, macrocephaly and brain abnormalities, associated with impaired nuclear functions of PTEN-R173C, demonstrated by reduced dsDNA damage repair. We integrated PHTS patient data with our mouse model results, and propose that defective nuclear functions of PTEN variants can predict the onset of PHTS phenotypes and that late-onset cancer in these individuals may arise from secondary genetic alterations, facilitated by compromised dsDNA repair.