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PubMed2025

Divergent PTEN-p53 interaction upon DNA damage in a human thyroid organoid model with germline PTEN mutations.

Germline mutations in the tumor suppressor phosphatase and tensin homolog (PTEN) cause PTEN hamartoma tumor syndrome (PHTS). PHTS is characterized by an elevated lifetime risk of differentiated thyroid cancer (DTC), 30 times higher than the general population. However, only 1 in 3 PHTS patients develop DTC, and it remains unknown whether specific PTEN variants are associated with an increased risk of DTC. PTEN antagonizes the phosphatidylinositol 3-kinase (PI3K)-AKT signaling pathway, a frequently affected pathway in sporadic DTC. PTEN also acts as a guardian of the genome by interacting with other tumor suppressors. Here, we report how ionizing radiation, an environmental tumorigenic contributor, modifies the DNA damage response based on the type of germline PTEN variants. We hypothesized that certain PTEN variants associated with DTC create a pro-oncogenic molecular signature upon radiation-induced DNA damage. DTC-associated (PTEN M134R ) or DTC-non-associated (PTEN G132D ) germline PTEN mutant alleles were introduced into a human induced pluripotent cell (hiPSC) line derived from a healthy donor utilizing CRISPR-Cas9 gene editing technology. We determined radiation-induced transcriptomic changes in functional thyroid organoids induced from wild-type and both heterozygous PTEN mutant hiPSCs. Both bulk and single-cell RNA sequencing data indicated that radiation upregulated the p53 network more potently in the thyroid organoids with PTEN WT/G132D than those with PTEN WT/M134R , which could be mediated by AKT-dependent MDM2 inactivation and PTEN-p53 physical interaction. Our data suggest that the lack of p53 pathway activation through PTEN-p53 network interactions explains why PTEN M134R is a DTC-susceptible variant.

Humans↗

PubMed2026

Recognizing genetic association between Lhermitte-Duclos Disease and Autism Spectrum Disorder in PTEN-related patients: a case report and literature comprehension.

BACKGROUND: PTEN Hamartoma Tumor Syndrome (PHTS) is a rare autosomal dominant disorder that increases the risk of various tumors and systemic malignancies, including Lhermitte-Duclos disease (LDD), known as dysplastic cerebellar gangliocytoma. Both conditions result from a PTEN gene mutation, which disrupts cellular growth and proliferation. Some children with such a mutation exhibit developmental delay or autism spectrum disorder (ASD), associated with PHTS. Herein, we report on a mother with LDD/PHTS and her child with ASD, discuss screening, genetic counseling, and management of PHTS-affected, PTEN-related, family-connected patients, and provide a narrative literature review. METHODS: Clinical and diagnostic evaluation and genetic analysis were performed on a female patient with LDD/PHTS and on her 14-year-old daughter, diagnosed with ASD. Genomic DNA was extracted from the peripheral blood of both, using a commercial DNA isolation kit to detect a PTEN mutation. RESULTS: Ten-year follow-up of the LDD/PHTS patient showed no evidence of tumor recurrence after partial tumor resection, resulting in full neurological recovery. Genetic testing of both the mother and her child confirmed the same genetic variant-PTEN c.370 T > C p.(Cys124Arg), NM_000314.8, in heterozygous status-classified as pathogenic for PHTS. CONCLUSIONS: This paper highlights the importance of timely diagnosis of PHTS in an ASD-affected child after identifying a parent with LDD/PHTS, a disorder with significant implications linked to a PTEN mutation. Given the risk of malignancy and neurodevelopmental disorders associated with PTEN mutation, patients suspected of having LDD/PHTS and children with ASD should undergo regular screening for PTEN-related diseases and receive appropriate genetic counseling.

Humans↗

PubMed2026

Phenotypic manifestations and variant reclassification of germline PTEN variants: a nationwide Danish study.

BACKGROUND: Classification of heterozygous germline PTEN variants in patients with, or suspected of having, PTEN hamartoma tumour syndrome (PHTS) remains challenging. Accurate classification is essential as these patients require lifelong cancer surveillance. METHODS: We identified all patients with a PTEN variant previously classified as a variant of uncertain significance (VUS), likely pathogenic (LP) or pathogenic (P), collected clinical data and reclassified all variants using the latest PTEN gene-specific American College of Medical Genetics (ACMG) guidelines. Moreover, genotype-phenotype correlations were assessed. RESULTS: 167 patients from 112 families were enrolled. Eighty-seven unique PTEN variants were identified, including 20 novel variants. After applying the PTEN gene-specific ACMG guidelines, 32 variants (36.8%) were reclassified, resulting in 60 PTEN variants classified as LP/P (69.0%), 18 variants classified as VUS (20.7%), while 9 variants were classified as LB/B (10.3%). Genotype-phenotype correlation was performed among 104 patients with LP/P variants: 51 cancer cases were recorded in 41 patients and a distinct PHTS phenotype was observed in 25% of patients, with macrocephaly being present in 99% of patients with a known head circumference. Twenty-three patients had neurodevelopmental delay and/or autism, and we observed an increased prevalence of missense variants in these patients. CONCLUSION: We identified 87 different PTEN variants, and application of PTEN gene-specific ACMG guidelines led to reclassification of 32 variants (36.8%), underscoring the importance of regular variant reassessment using the most recent gene-specific guidelines, ensuring optimal patient management and surveillance.

Genetic Predisposition to Disease↗

PubMed2026

Phenylalanine 347 regulates the subcellular localization of PTEN.

PTEN plays diverse tumor-suppressive roles, including inhibition of PI3K-AKT signaling and maintenance of genomic integrity in the nucleus. Elucidating the molecular mechanisms regulating its subcellular localization is therefore essential for understanding PTEN functions. PTEN350, a fragment comprising the N-terminal phosphatase and C2 domains of PTEN, preferentially localizes to the nucleus, although the residues responsible for this localization remain unclear. Previously, we demonstrated that Thr348 contributes to the prominent nuclear accumulation of the PTEN350 fragment and PTENA4 carrying alanine substitutions in the Ser380/Thr382/Thr383/Ser385 (STTS) motif. Since our previous findings suggested that Phe347 also contributes to PTEN nuclear localization, we investigated its role in the present study. Phe347 substitutions (F347A, F347Y, and F347L) were introduced into PTEN and its mutant or truncated derivatives, including PTEN350, PTEN, PTENA4, PTEN350,K13R, and PTENK13R,A4, either alone or in combination with T348D. The F347A substitution significantly attenuated the nuclear accumulation of PTEN350 and PTENA4, whereas F347L partially preserved nuclear accumulation and F347Y substitution exhibited an intermediate phenotype. Similar effects of the F347 substitutions were also observed in the T348D mutants, although the differences among the three substitutions were less pronounced. A similar pattern was observed for the plasma membrane localization of PTEN350,K13R and PTENK13R,A4, with F347A causing the greatest reduction, F347L retaining partial membrane localization, and F347Y exhibiting an intermediate phenotype. The effects of these substitutions were consistently observed in both HEK293T cells and HeLa cells. Collectively, these findings indicate that Phe347 is an important determinant of PTEN subcellular localization.

Nuclear translocation↗

PubMed2025

Corticotropin-releasing hormone inhibits autophagy by suppressing PTEN to promote apoptosis in dermal papilla cells.

BACKGROUND: Stress-related hair loss is on the rise, largely due to escalating levels of stress-related corticotropin-releasing hormone (CRH) through poorly defined mechanisms. CRH-mediated activation of corticotropin-releasing hormone receptors (CRHRs) on dermal papilla cells (DPCs) is a likely cause of stress-related hair loss. The aim of the study is to elucidate the key mechanisms of alopecia caused by CRH and provide potential new targets for the treatment of stress-related hair loss. METHODS: 4D label-free quantitative proteomics of DPCs and the chronic unpredictable mild stress mouse (CUMS) model were used to explore the relationship and mechanism between CRH, DPCs and hair regeneration. RESULTS: CRH initially downregulated PTEN to suppress autophagy, leading to DPC apoptosis. Overexpression of PTEN enhanced autophagy and mitigated CRH-dependent DPC apoptosis. CRH inhibited PTEN and activated the PI3K/AKT/mTOR pathway, whereas rapamycin inhibited this pathway and activated autophagy, consequently lowering apoptosis, suggesting that increased susceptibility to apoptosis is caused by decreased autophagy. CUMS-induced hair growth disruption is accompanied by an increase in CRHRs and a decrease in PTEN levels within the dermal papilla. Intracutaneous injection of CRH impeded hair regeneration and decreased PTEN in mice, concurrent with inhibition of autophagy and increased apoptosis. CONCLUSIONS: These findings indicate that PTEN loss coupled with PI3K/AKT/mTOR-mediated autophagy inhibition and apoptosis in DPCs is a key mechanism of stress-related hair loss induced by CRH and suggests that topical activation of PTEN or enhancement of autophagy, e.g. through rapamycin, may have a therapeutic effect on stress-induced hair loss disorders such as alopecia.

Animals↗

PubMed2026

A spotlight on PTEN alterations in prostate cancer: A narrative review.

Among the molecular alterations observed in prostate cancer, PTEN loss represents a key event, functionally linked to aberrant activation of the PI3K/AKT/mTOR pathway. Loss of PTEN function contributes to disease progression, therapy resistance and poor prognosis. This review highlights the biological significance and the prognostic role of PTEN in prostate cancer, the biologically relevant crosstalk between the PI3K and androgen receptor pathways, and the implications of this interaction for tumour adaptation and treatment resistance. We also discuss current methodologies for PTEN assessment, including immunohistochemistry and genomic techniques, and provide an overview of clinical trials targeting the PI3K/AKT axis in prostate cancer. Understanding PTEN alterations is essential for improving prognostic stratification and guiding precision oncology approaches.

Humans↗

PubMed2026

Reversible exacerbation of parkinsonism during epirubicin-cyclophosphamide chemotherapy in a patient with PTEN hamartoma tumor syndrome and young-onset Parkinson's disease.

BACKGROUND: PTEN hamartoma tumor syndrome (PHTS), caused by germline loss-of-function variants in PTEN, typically manifests as macrocephaly, neurodevelopmental disorders, and cancer susceptibility. Parkinson's disease has not been recognized as part of its known neurological spectrum. METHODS: We describe the clinical course of a patient with a germline PTEN nonsense variant (p.Arg130Ter) who developed young-onset Parkinson's disease before being diagnosed with bilateral breast cancer. RESULTS: The patient developed asymmetric, levodopa-responsive parkinsonism at 35 years of age, with reduced bilateral striatal dopamine transporter uptake. During two cycles of epirubicin-cyclophosphamide chemotherapy, her previously well-controlled parkinsonism showed reproducible and severe exacerbations. Symptoms began several days after chemotherapy, reached their maximum severity approximately one week after treatment, and resolved completely within approximately two weeks without modification of her antiparkinsonian medications. No dehydration, electrolyte disturbance, infection, or exposure to dopamine-receptor antagonists was identified. The chemotherapy regimen was discontinued after the second episode because of the reproducible temporal association. CONCLUSIONS: This case demonstrates reproducible, fully reversible exacerbations of parkinsonism during epirubicin-cyclophosphamide chemotherapy in a patient with PHTS and young-onset Parkinson's disease. These episodes may reflect transient vulnerability of dopaminergic neurons to chemotherapy-related systemic stress, although the causal role of PTEN haploinsufficiency remains uncertain.

Humans↗

PubMed2026

Gene-environment interaction between perinatal oxytocin exposure and Pten mutation shapes epigenetic reprogramming of oxytocin signaling and behavior in mice.

Synthetic oxytocin (Pitocin) is the most commonly used pharmacologic agent for induction and augmentation of labor. Beyond its uterotonic effects, oxytocin plays a critical role in neurodevelopment and social behavior. Dysregulated oxytocin signaling has been implicated in autism spectrum disorder (ASD), raising concern that perinatal exposure to exogenous oxytocin may have lasting neurodevelopmental consequences. This study aimed to determine whether offspring harboring a genetic predisposition for ASD are differentially impacted by perinatal oxytocin exposures, with a focus on long-term oxytocin signaling and autism-like behavior. Pregnant mice carrying offspring with heterozygous mutations in phosphatase and tensin homolog deleted on chromosome ten (Pten), a well-established monogenic risk factor for ASD, received continuous oxytocin versus phosphate-buffered saline (PBS) control via micro-osmotic pumps during late gestation. Wild-type (WT) offspring exposed to each treatment served as a secondary control. Adult offspring were assessed for oxytocin receptor (Oxtr) methylation in the frontal cortex and hippocampus, oxytocin expression in the hypothalamus, serum oxytocin levels, and were subject to a battery of social and anxiety-related behavior tests. Perinatal oxytocin exposure produced genotype-dependent effects in offspring. Epigenetic analyses revealed bidirectional remodeling of Oxtr methylation in the frontal cortex and hippocampus, with increased exon 1 methylation in WT mice and decreased methylation in Pten-mutant mice, resulting in significant genotype-treatment interactions. Hypothalamic oxytocin expression increased following treatment regardless of genotype, though baseline levels were higher in Pten-mutant mice. Neither oxytocin treatment nor genotype impacted long-term serum oxytocin levels. Behavioral outcomes were modest but context-specific: repetitive behaviors and cognition performance were unchanged, but oxytocin-treated Pten-mutant mice exhibited increased anxiety-like behavior alongside improved social memory. In contrast, oxytocin-treated WT mice showed reduced social novelty preference. Exploratory analyses suggested potential sex-dependent trends. Our findings support a model in which genetic susceptibility shapes the epigenetic encoding of early-life hormonal signals, thereby recalibrating oxytocin system function and downstream behavioral outcomes. Together, these data highlight the context-dependent effects of perinatal oxytocin exposure and argue against uniformly beneficial or detrimental effects, emphasizing the importance of gene-environment interactions in neurodevelopmental trajectories.

Animals↗

PubMed2025

The risk of a second primary cancer in PTEN Hamartoma Tumor Syndrome (PHTS).

PURPOSE: Patients with PTEN Hamartoma Tumor Syndrome (PHTS) have high hereditary cancer risks for breast, endometrial, and thyroid cancer. Patients develop multiple primary cancers, but these risks remain uncertain. We aimed to provide the second primary cancer risk. METHODS: This European cohort study assessed second primary cancer risks with Kaplan-Meier analyses using data from medical files, registries and/or patient questionnaires. RESULTS: Overall, 279 adult PHTS patients with (a history of) cancer were included (80% female). Among females, 106 (54%) developed a PHTS-related second primary cancer after a PHTS-related first primary cancer, whereas 10 (29%) males developed a PHTS-related second primary cancer after a PHTS-related first primary cancer. The 5- and 10-year PHTS-related second primary cancer risks were 24.5% (95% CI = 18.1-32.5) and 45.7% (95% CI = 36.9-55.4) in females and 14.5% (95% CI = 5.7-34.1) and 19.8% (95% CI = 8.6-41.9) in males, respectively. Furthermore, 5- and 10-year risks for a second primary breast cancer after a first primary breast cancer were 23.3% (95% CI = 14.9-35.2) and 45.6% (95% CI = 33.0-60.2) in females, respectively. CONCLUSION: This study demonstrated that PHTS patients have high second primary cancer risks, which is driven by breast cancer in females. Hence, identifying patients with PHTS before or at first primary cancer diagnosis is essential to enable potential early detection or prevention of a second primary cancer through surveillance or risk-reducing surgery.

Humans↗

PubMed2026

Correction: Germline nuclear-predominant Pten murine model exhibits impaired social and perseverative behavior, microglial activation, and increased oxytocinergic activity.

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Published Erratum↗

PubMed2026

Impact of Genomic Mutations on the Transcriptional Pathways and Tumor Microenvironment Landscape of Localized Early Prostate Cancer.

BACKGROUND: The management of intermediate-risk early prostate cancer (PCa) is challenging due to the difficulty in distinguishing indolent from aggressive tumors. This study explores the association between genomic alterations and the tumor and its microenvironment (TME) and implications for disease progression. METHODS: We performed multi-omic profiling in a cohort of 53 localized PCa using targeted sequencing, transcriptional, and proteomic spatial profiling. RESULTS: Somatic mutations and copy number alterations in RB1 (21%), PTEN (18%), and TP53 (9%) were identified. Kaplan-Meier analysis revealed that alterations in the RB and Cell Cycle pathways, particularly aberrations in PTEN, TP53, or RB1, were associated with shorter biochemical recurrence-free survival (p < 0.001). Spatial proteomic analysis demonstrated a complex immune landscape in patients with mutations. The tumor compartment demonstrated higher expression of immune checkpoint markers, T-cell activation proteins, and proliferation markers; and a TME that is enriched with CD8 + T cells and antigen-presenting cells, but also with immunosuppressive M2 macrophages, suggesting adaptive immune resistance. CONCLUSIONS: Our analysis demonstrates that genomic alterations in PTEN, TP53, or RB1 are not only prognostic for poor outcomes but are also associated with a unique, immunologically complex TME in this Brazilian cohort.

Humans↗

PubMed2026

A Biomimetic Dual-Targeting Nano-APA-Editor Reprograms the 3'UTR Landscape for Tongue Squamous Cell Carcinoma Therapy.

Targeting post-transcriptional dysregulation of tumor suppressors represents a new frontier in cancer therapy. Here, we identify the alternative polyadenylation (APA) regulator NUDT21 as a pivotal therapeutic target in oral squamous cell carcinoma (OSCC). NUDT21 is highly upregulated, correlating strongly with poor survival and advanced clinical stage. We outline a pathogenic mechanism whereby NUDT21 drives this phenotype by forcing a network of tumor suppressor transcripts, notably PTEN, into translationally-repressed, long-3'UTR isoforms. To therapeutically "re-engineer" this APA switch, we design a "Nano-APA-editor." This platform features an HMSN core with an sgRNA-NUDT21 payload and a hierarchical targeting strategy: a cancer-educated dendritic cell (DC) membrane for biomimetic camouflage and homotypic affinity, "gated" by a TA-aptamer for final precision. This system enables potent and selective NUDT21 silencing, driving a shift toward short-3'UTR isoforms. Consequently, the Nano-APA-editor effectively reinstates PTEN and associated suppressors and inhibits multiple malignant phenotypes in vitro. In an orthotopic OSCC model, it demonstrates profound tumor regression, outperforming conventional chemotherapy (PTX) with excellent biocompatibility. In vivo analysis confirmed target engagement (NUDT21-down) and functional restoration (PTEN-, WEE1-, TGF-β-up). This work validates a "post-transcriptional re-engineering" strategy, executed by a logically designed nanoplatform, as a powerful and safe modality for precision gene therapy.

Humans↗

PubMed2025

Genomic profiling of aggressive pathologic features in lung adenocarcinoma.

INTRODUCTION: Pathologic features involving LVI (lympho-vascular invasion), PNI (perineural invasion), STAS (spread through air spaces), and Grade 3 pattern (from the International Association for the Study of Lung Cancer grading system) are related to having an aggressive phenotype and linked to poor prognosis. However, few studies have conducted in-depth analyses of these features simultaneously with genomic profiling. METHODS: A total of 1559 sequencing of adenocarcinoma samples were included in the common driver mutations analysis, 1306 samples were brought into genomic mapping analysis. OncoSG's East Asian ancestry dataset was implemented for Tumor-Node-Metastasis-Biomarker (TNMB) classification and prognostic assessment. RESULTS: EGFR was more significantly prevalent in LVI negativity (P = 0.021), STAS negativity (P = 0.002), and moderate grade (P < 0.001). ALK was significantly interrelated with LVI (P = 0.028), STAS (P < 0.001), and poor grade (P < 0.001); ROS1 and STAS positivity (P = 0.031), poor grade (P = 0.016) were significantly related. KRAS (P = 0.003) and BRAF-V600E (P = 0.002) were only significantly intertwined with poor grade. Apart from common driver mutations, TP53, CHEK2, KEAP1, PTEN, RB1, NF1 were significantly enriched in LVI samples (P < 0.05). TP53, PTEN, CTNNB1, HGF, NF1 were more prominent in STAS (P < 0.01). TP53, LRP1B, NF1 were significantly more prevalent in Grade 3 pattern (P < 0.001). The mixture of STK11, PTEN, and TOP2A generated by exclusive mutations may be a potential predictor of TNMB categorization towards survival. The HR of stage II compared I of TNMB was 2.28 (95 % CI 1.36-3.86, P < 0.001), while stage III compared II was 1.95 (95 % CI 1.04-3.21, P = 0.031). CONCLUSIONS: This analysis demonstrated the correlation of pathologic features with common driver mutations, key mutations and canonical oncogenic signaling pathways. The data highlighted the similarities and differences among these features horizontally, and provide new insights in TNMB classification and prognostic assessment.

Humans↗

PubMed2017

MicroRNA‑27a promotes tumorigenesis via targeting AKT in triple negative breast cancer.

Altered microRNA (miRNA/miR) expression regulates tumor development and progression in triple‑negative breast cancer (TNBC). The present study examined the effect of miR‑27a on proliferation, migration and invasion of TNBC cells in vitro and in vivo. An MTT assay was performed to examine the proliferation of MDA‑MB‑231 and MDA‑MB‑468 breast cancer cells with either overexpression of miR‑27a or downregulation of miR‑27a, in the presence or absence of radiation. The migratory and invasive abilities of MDA‑MB‑231 and MDA‑MB‑468 breast cancer cells were assessed by Transwell migration and Matrigel invasion assays. The protein expression levels were examined by western blotting. The caspase‑Glo3/7 assay was performed to examine the effect of miR‑27a on radiation‑induced apoptosis in MDA‑MB‑231 and MDA‑MB‑468 breast cancer cells. A luciferase assay was performed to evaluate the effect of miR‑27a on phosphatase and tensin homolog (PTEN) and B cell lymphoma (Bcl)‑2 associated X, apoptosis regulator (BAX) expression. Immunodeficient nude mice were used to examine tumor growth following injection of MDA‑MB‑231 breast cancer cells. miR‑27a promoted proliferation in vitro and in vivo, and enhanced migration and invasion in TNBC cells. miR‑27a improved the survival of TNBC cells following irradiation. miR‑27a inhibited radiation‑induced apoptosis in TNBC cells by regulation of caspase 3/7 and Bcl‑2 expression. Furthermore, the expression levels of PTEN and phosphorylated protein kinase B in MDA‑MB‑231 and MDA‑MB‑468 cells was altered following overexpression of miR‑27a. The luciferase assay demonstrated that miR‑27a regulated PTEN and BAX expression by binding to 3'‑untranslated regions. Overall, miR‑27a exhibits an essential role in tumor development and progression in TNBC and may be used as a potential biomarker to predict radiotherapy response and prognosis for the disease.

3' Untranslated Regions↗

PubMed2026

MicroRNA-181a-5p promotes papillary thyroid carcinoma progress via the PTEN/AKT pathway.

The objective of this investigation was to determine the expression profile and latent mechanism of microRNA-181a-5p (miR-181a-5p) in the genesis and progression of papillary thyroid cancer (PTC). MiR-181a-5p was discovered to be upregulated in PTC tissues and cells in this study, as confirmed by RT‒qPCR and The Cancer Genome Atlas database. Notably, in PTC patients, the miR-181a-5p level was linked to tumor size and thyroid capsule invasion. A series of experiments demonstrated that miR-181a-5p upregulation in PTC cells notably enhanced proliferation, motility, and invasion, whereas suppressing miR-181a-5p hindered these functions. Western blotting revealed that miR-181a-5p suppressed PTEN expression, boosting the activation of phosphorylated AKT (P-AKT). According to predictive bioinformatics research and luciferase reporter gene tests, miR-181a-5p may target a specific binding site on the PTEN 3'UTR. To sum up, this study indicated that miR-181a-5p promoted PTC progression through the PTEN/Akt pathway. This investigation reveals a potential mechanism for PTC progression and provides a foundation for clinical therapies.

MicroRNAs↗

PubMed2026

DNA copy number patterns reveal prognostic markers and elucidate mechanisms of evolution in IDH-mutant astrocytoma.

BACKGROUND: Current literature suggestsisocitrate dehydrogenase (IDH)-mutant astrocytoma contains several molecular subgroups. In this study, we are interested in determining the connection between different molecular subgroups with grade and/or survival. METHODS: A cohort of 470 Mayo Clinic adult patients (≥18 years, 56.2% male) with primary IDH-mutant astrocytoma diagnosed by World Health Organization (WHO) 2021 criteria were examined. Results were validated in an independent cohort of 614 Mayo Clinic Neuropathology consult patients and 235 The Cancer Genome Atlas (TCGA) patients. RESULTS: The Mayo Clinic Practice cohort confirmed the association of CDKN2A/B deletion with overall survival (OS, homozygous vs hemizygous vs intact, 2.7 vs 9.6 vs 17.2 years, P < .001). Phosphatase and tensin homolog (PTEN) deletion was also associated with poor OS (7.3 vs 17.4 years, P < .001). Increased number of copy number alterations was associated with OS (continuous variable, HR = 1.027, P < .001). Carrying one or more copies of the germline risk allele at rs55705857 was associated with earlier age of onset (median age 33 vs 35 years, P = .01), and a shorter OS after adjusting for age, grade, sex and treatment (HR = 1.81, P = .007). The Mayo Clinic Neuropathology Consult cohort and TCGA were utilized to validate age of onset and survival, respectively. Unsupervised clustering of the copy number alterations identified several clinically significant groups that may define pathways to disease progression. Losses of chromosomes 11p, 13q, 1p, and 10q were all associated with reduced overall survival in the Mayo Clinic cohort. CONCLUSIONS: Patients with hemizygous loss of CDKN2A/B, loss of PTEN, increased number of copy number alterations, specific chromosomal arm losses or rs55705857 germline risk allele have reduced overall survival.

Humans↗

PubMed2026

A PMS2-deficient pediatric high-grade glioma with PI3K-pathway mutations and adjacent developmental venous anomaly suggestive of CMMRD.

PURPOSE: Constitutional mismatch repair deficiency (CMMRD) is a rare hereditary cancer predisposition syndrome that frequently manifests with pediatric high-grade gliomas. However, recognition remains challenging, particularly in the absence of a clear family history. We report a pediatric high-grade glioma with PMS2 deficiency and complex molecular alterations to highlight key diagnostic clues and the importance of routine mismatch repair assessment. METHODS: Clinical, radiological, histopathological, immunohistochemical, and molecular findings of an 8-year-old girl presenting with a high-grade glioma were retrospectively evaluated. Immunohistochemistry included glial and mismatch repair markers. Targeted next-generation sequencing was performed to assess tumor mutational burden and pathogenic variants. RESULTS: Neuroimaging revealed a right frontoparietal mass associated with an adjacent developmental venous anomaly. Histopathology demonstrated a diffuse pediatric-type high-grade glioma with pseudopapillary architecture and marked mitotic activity. Immunohistochemistry showed diffuse p53 overexpression in tumor cells and complete loss of PMS2 expression in both tumor and non-neoplastic cells, supporting constitutional mismatch repair deficiency. Molecular analysis revealed an ultra-hypermutated profile with a tumor mutational burden of 117.4 mutations/Mb, a pathogenic PMS2 frameshift variant, and co-occurring alterations in TP53, PIK3CA, PIK3R1, and PTEN. The presence of PI3K-pathway mutations alongside a venous anomaly suggested a potential biological association. CONCLUSION: This case illustrates the characteristic clinicopathological and molecular features of CMMRD-associated pediatric high-grade glioma and underscores the critical role of routine mismatch repair immunohistochemistry. Integrated histological and genomic evaluation is essential for accurate diagnosis, appropriate genetic counseling, and potential therapeutic implications. Key Points • This case represents a pediatric high-grade glioma arising in the setting of PMS2-related constitutional mismatch repair deficiency (CMMRD). • The tumor exhibited an ultra-hypermutated profile with co-occurring TP53, PIK3CA, PIK3R1, and PTEN mutations. • Loss of PMS2 expression in both tumor and non-neoplastic cells was critical in establishing the diagnosis of CMMRD. • The presence of a developmental venous anomaly may relate to underlying PIK3R1 pathway alterations. • Routine mismatch repair immunohistochemistry is essential in pediatric high-grade gliomas, even in the absence of a family history.

Humans↗

PubMed2026

Emerging Strategies Targeting the PI3K/AKT/mTOR Pathway in HR+/HER2- Advanced Breast Cancer.

Hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) breast cancer accounts for approximately 70% of breast cancer cases. Despite recent advances with cyclin-dependent kinase 4/6 inhibitors (CDK4/6i), resistance inevitably develops, often driven by activation of the phosphatidylinositol 3-kinase (PI3K)-AKT-mammalian target of rapamycin (mTOR) pathway. Genetic alterations such as PIK3CA mutations (present in ~ 45% of HR+/HER2- tumors), AKT1 mutations, and PTEN loss contribute to endocrine resistance and poor outcomes. This review summarizes emerging strategies targeting this pathway to overcome resistance in advanced disease. Isoform-specific PI3K inhibitors, including alpelisib and inavolisib, have demonstrated clinically meaningful progression-free survival benefits in PIK3CA-mutated populations, with inavolisib showing improved tolerability and efficacy. In contrast, pan-PI3K inhibitors such as buparlisib have been constrained by toxicity. Targeting downstream signaling, AKT inhibitors have also shown benefit: capivasertib has demonstrated clinical efficacy leading to US Food and Drug Administration approval, while ipatasertib has yielded encouraging results, particularly in tumors harboring PIK3CA, AKT1, or PTEN alterations. Mammalian target of rapamycin inhibitors, notably everolimus, have shown efficacy irrespective of mutation status. The dual PI3K-mTOR inhibitor (gedatolisib) has also shown promising progression-free survival benefit in a PIK3CA wild-type population. Next-generation agents, including mutant-selective PI3Kα inhibitors and bi-steric mTOR complex 1 inhibitors, are under active investigation. Optimal sequencing of these agents alongside endocrine therapy and CDK4/6i options remain a critical question, as does integration of genomic testing to guide therapy. Future directions include rational combination strategies, improved biomarker-driven selection, and novel modalities such as proteolysis-targeting chimeras (PROTACs). Collectively, these advances aim to enhance durability of response, minimize toxicity, and improve survival in HR+/HER2- metastatic breast cancer.

Humans↗