Germline mutations of the PTEN gene in Cowden disease, an inherited breast and thyroid cancer syndrome

PTPN4 germline variants result in aberrant neurodevelopment and growth

Protein-tyrosine phosphatases (PTPs) are pleomorphic regulators of eukaryotic cellular responses to extracellular signals that function by modulating the phosphotyrosine of specific proteins. A handful of PTPs have been implicated in germline and somatic human disease. Using exome sequencing, we identified missense and truncating variants in PTPN4 in six unrelated individuals with varying degrees of intellectual disability or developmental delay. The variants occurred de novo in all five subjects in whom segregation analysis was possible. Recurring features include postnatal growth deficiency or excess, seizures, and, less commonly, structural CNS, heart, or skeletal anomalies. PTPN4 is a widely expressed protein tyrosine phosphatase that regulates neuronal cell homeostasis by protecting neurons against apoptosis. We suggest that pathogenic variants in PTPN4 confer risk for growth and cognitive abnormalities in humans.

Pharmacological mechanism of mylabris in the treatment of leukemia based on bioinformatics and systematic pharmacology

Leukemia is a common blood cancer, whose treatment usually necessitates chemo/radiotherapy and bone marrow transplant. Hence, safer and more effective options are urgently needed. Mylabris, the dried body of blister beetles, has been used extensively in traditional Chinese medicine. This study applied bioinformatics and systematic pharmacology to investigate the mechanism of action of mylabris in the treatment of leukemia. Five effective components and 35 corresponding target proteins were identified by screening the TCMSP database; whereas 776 genes related to leukemia were selected using OMIM, GeneCards, and the Therapeutic Target Database. Eight genes common to mylabris and leukemia were identified. Protein-protein interaction network analysis and a component-target-pathway diagram identified TP53 and PTEN as key gene targets of mylabris in the treatment of leukemia. GO enrichment analysis pointed to DNA damage and cell cycle disorder caused by p53 signaling as the most significant processes; whereas KEGG enrichment pointed to the p53 signaling pathway. In summary, mylabris may exert a therapeutic effect on leukemia by triggering DNA damage, inducing apoptosis, as well as inhibiting the growth and proliferation of tumor cells through the regulation of TP53 and PTEN. These findings provide a mechanistic rationale for the treatment of leukemia with traditional Chinese medicine.

Redefining the PTEN promoter: Identification of novel upstream transcription start regions

Germline mutation of PTEN is causally observed in Cowden syndrome (CS) and is one of the most common, penetrant risk genes for autism spectrum disorder (ASD). However, the majority of individuals who present with CS-like clinical features are PTEN-mutation negative. Reassessment of PTEN promoter regulation may help explain abnormal PTEN dosage, as only the minimal promoter and coding regions are currently included in diagnostic PTEN mutation analysis. Therefore, we reanalyzed the architecture of the PTEN promoter using next-generation sequencing datasets. Specifically, run-on sequencing assays identified two additional transcription start regions (TSRs) at -2053 and - 1906 basepairs from the canonical start of PTEN, thus extending the PTEN 5'UTR and redefining the PTEN promoter. We show that these novel upstream TSRs are active in cancer cell lines, human cancer, and normal tissue. Further, these TSRs can produce novel PTEN transcripts due to the introduction of new splice donors at -2041, -1826, and - 1355, which may allow for splicing out of the PTEN 5'UTR or the first and second exon in upstream-initiated transcripts. Combining ENCODE ChIP-seq and pertinent literature, we also compile and analyze all transcription factors (TFs) binding at the redefined PTEN locus. Enrichment analyses suggest that TFs bind specifically to the upstream TSRs may be implicated in inflammatory processes. Together, these data redefine the architecture of the PTEN promoter, an important step toward a comprehensive model of PTEN transcription regulation, a basis for future investigations into the new promoters' role in disease pathogenesis.

Advances in colorectal cancer genomics and transcriptomics drive early detection and prevention

Colorectal carcinoma (CRC) is a high incidence cancer and leading cause of cancer mortality worldwide. The advances in genomics and transcriptomics in the past decades have improved the detection and prevention of CRC in familial CRC syndromes. Nevertheless, the ultimate goal of personalized medicine for sporadic CRC is still not within reach due no less to the difficulty in integrating population disparity and clinical data to combat what essentially is a very heterogenous disease. This minireview highlights the achievement of the past decades and present possible direction in the hope of early detection and metastasis prevention for reducing CRC-associated morbidity and mortality.

Genetic Basis and Therapies for Vascular Anomalies

Vascular and lymphatic malformations represent a challenge for clinicians. The identification of inherited and somatic mutations in important signaling pathways, including the PI3K (phosphoinositide 3-kinase)/AKT (protein kinase B)/mTOR (mammalian target of rapamycin), RAS (rat sarcoma)/RAF (rapidly accelerated fibrosarcoma)/MEK (mitogen-activated protein kinase kinase)/ERK (extracellular signal-regulated kinases), HGF (hepatocyte growth factor)/c-Met (hepatocyte growth factor receptor), and VEGF (vascular endothelial growth factor) A/VEGFR (vascular endothelial growth factor receptor) 2 cascades has led to the evaluation of tailored strategies with preexisting cancer drugs that interfere with these signaling pathways. The era of theranostics has started for the treatment of vascular anomalies. Registration: URL: https://www.clinicaltrialsregister.eu; Unique identifier: 2015-001703-32.

PTEN Activity Defines an Axis for Plasticity at Cortico-Amygdala Synapses and Influences Social Behavior

Phosphatase and tensin homolog on chromosome 10 (PTEN) is a tumor suppressor and autism-associated gene that exerts an important influence over neuronal structure and function during development. In addition, it participates in synaptic plasticity processes in adulthood. As an attempt to assess synaptic and developmental mechanisms by which PTEN can modulate cognitive function, we studied the consequences of 2 different genetic manipulations in mice: presence of additional genomic copies of the Pten gene (Ptentg) and knock-in of a truncated Pten gene lacking its PDZ motif (Pten-ΔPDZ), which is required for interaction with synaptic proteins. Ptentg mice exhibit substantial microcephaly, structural hypoconnectivity, enhanced synaptic depression at cortico-amygdala synapses, reduced anxiety, and intensified social interactions. In contrast, Pten-ΔPDZ mice have a much more restricted phenotype, with normal synaptic connectivity, but impaired synaptic depression at cortico-amygdala synapses and virtually abolished social interactions. These results suggest that synaptic actions of PTEN in the amygdala contribute to specific behavioral traits, such as sociability. Also, PTEN appears to function as a bidirectional rheostat in the amygdala: reduction in PTEN activity at synapses is associated with less sociability, whereas enhanced PTEN activity accompanies hypersocial behavior.

Orofacial Manifestations Assisting the Diagnosis of Cowden Syndrome in a Middle-Aged Patient: Case Report and Literature Overview

Middle-aged and old adults (≥ 50 years) diagnosed with Cowden syndrome (CS) with orofacial manifestations are uncommon. We describe a case of CS in a 53-year-old female showing "narrow bird-like" face, macrocephaly, acral keratoses, oral candidiasis, burning in the mouth, and multiple asymptomatic papillomatous lesions with a cobblestone pattern distributed on the alveolar ridge, tongue, buccal mucosa, and commissure. The histopathological features of lesions of the oral mucosa were those of papillary fibroepithelial hyperplasia. Immunohistochemistry revealed strong positivity for PTEN and p53 in most epithelial cells, while the expression of Bcl-2, S-100, and Ki-67 was weak/negative. According to a review conducted in PubMed, Web of Science, Embase, and Scopus for the analysis of reports of CS individuals ≥ 50 years with orofacial manifestations, 56 cases have been described in literature. Predilection for women was observed, with a female:male ratio of 2.3:1. Thirty-five (62.5%) individuals developed some malignant neoplasms. Oral health providers should be aware of the orofacial aspects of CS, including multiple papillomatosis, which can be an important criterion for diagnosis. Since malignancies may occur in older adults with CS, the need for strict surveillance is necessary. The present case has been under follow-up for 7 years without evidence of other manifestations.

Reciprocal control of translation and transcription in autism spectrum disorder

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social communication and the presence of restricted patterns of interest and repetitive behaviors. ASD is genetically heterogeneous and is believed to be caused by both inheritable and de novo gene variations. Studies have revealed an extremely complex genetic landscape of ASD, favoring the idea that mutations in different clusters of genes interfere with interconnected downstream signaling pathways and circuitry, resulting in aberrant behavior. In this review, we describe a select group of candidate genes that represent both syndromic and non-syndromic forms of ASD and encode proteins that are important in transcriptional and translational regulation. We focus on the interplay between dysregulated translation and transcription in ASD with the hypothesis that dysregulation of each synthetic process triggers a feedback loop to act on the other, which ultimately exacerbates ASD pathophysiology. Finally, we summarize findings from interdisciplinary studies that pave the way for the investigation of the cooperative impact of different genes and pathways underlying the development of ASD.

Phosphatase and Tensin Homolog in Non-neoplastic Digestive Disease: More Than Just Tumor Suppressor

The Phosphatase and tensin homolog (PTEN) gene is one of the most important tumor suppressor genes, which acts through its unique protein phosphatase and lipid phosphatase activity. PTEN protein is widely distributed and exhibits complex biological functions and regulatory modes. It is involved in the regulation of cell morphology, proliferation, differentiation, adhesion, and migration through a variety of signaling pathways. The role of PTEN in malignant tumors of the digestive system is well documented. Recent studies have indicated that PTEN may be closely related to many other benign processes in digestive organs. Emerging evidence suggests that PTEN is a potential therapeutic target in the context of several non-neoplastic diseases of the digestive tract. The recent discovery of PTEN isoforms is expected to help unravel more biological effects of PTEN in non-neoplastic digestive diseases.

Nuclear PTEN deficiency and heterozygous PTEN loss have distinct impacts on brain and lymph node size

Defects in PTEN, a critical tumor suppressor, are associated with tumorigenesis and aberrant organ sizes. It has been shown that heterozygous PTEN loss increases brains and neuron size, while the specific loss of nuclear PTEN has the opposite effect. Here, we investigate the impact of a combination of heterozygous PTEN loss and nuclear PTEN loss on the size of various organs, including the brain, liver, thymus, spleen, and inguinal lymph node. We found that the effect of the combination varies among organs. Notably, the combination of heterozygous PTEN loss and nuclear PTEN loss restored the normal size of brains and neurons. In contrast, the liver's size was unaffected by either single PTEN defects or their combination. Strikingly, the size of the inguinal lymph node was greatly increased due to lymphoma by the combination of the two PTEN defects. These data suggest that nuclear PTEN and non-nuclear PTEN function in an antagonistic manner in the brain while acting synergistically in the inguinal lymph node.

Distinguishing between PTEN clinical phenotypes through mutation analysis

Phosphate and tensin homolog on chromosome ten (PTEN) germline mutations are associated with an overarching condition known as PTEN hamartoma tumor syndrome. Clinical phenotypes associated with this syndrome range from macrocephaly and autism spectrum disorder to Cowden syndrome, which manifests as multiple noncancerous tumor-like growths (hamartomas), and an increased predisposition to certain cancers. It is unclear, however, the basis by which mutations might lead to these very diverse phenotypic outcomes. Here we show that, by considering the molecular consequences of mutations in PTEN on protein structure and function, we can accurately distinguish PTEN mutations exhibiting different phenotypes. Changes in phosphatase activity, protein stability, and intramolecular interactions appeared to be major drivers of clinical phenotype, with cancer-associated variants leading to the most drastic changes, while ASD and non-pathogenic variants associated with more mild and neutral changes, respectively. Importantly, we show via saturation mutagenesis that more than half of variants of unknown significance could be associated with disease phenotypes, while over half of Cowden syndrome mutations likely lead to cancer. These insights can assist in exploring potentially important clinical outcomes delineated by PTEN variation.

Phakomatoses and Endocrine Gland Tumors: Noteworthy and (Not so) Rare Associations

Phakomatoses encompass a group of rare genetic diseases, such as von Hippel-Lindau syndrome (VHL), neurofibromatosis type 1 (NF1), tuberous sclerosis complex (TSC) and Cowden syndrome (CS). These disorders are due to molecular abnormalities on the RAS-PI3K-Akt-mTOR pathway for NF1, TSC and CS, and to hypoxia sensing for VHL. Phakomatoses share some phenotypic traits such as neurological, ophthalmological and cutaneous features. Patients with these diseases are also predisposed to developing multiple endocrine tissue tumors, e.g., pheochromocytomas/paragangliomas are frequent in VHL and NF1. All forms of phakomatoses except CS may be associated with digestive neuroendocrine tumors. More rarely, thyroid cancer and pituitary or parathyroid adenomas have been reported. These susceptibilities are noteworthy, because their occurrence rate, prognosis and management differ slightly from the sporadic forms. The aim of this review is to summarize current knowledge on endocrine glands tumors associated with VHL, NF1, TSC, and CS, especially neuroendocrine tumors and pheochromocytomas/paragangliomas. We particularly detail recent advances concerning prognosis and management, especially parenchyma-sparing surgery and medical targeted therapies such as mTOR, MEK and HIF-2 α inhibitors, which have shown truly encouraging results.

Familial non-medullary thyroid cancer: a critical review

BACKGROUND

Familial non-medullary thyroid carcinoma (FNMTC), mainly of papillary histotype (FPTC), is defined by the presence of the disease in two or more first-degree relatives in the absence of other known familial syndromes. With the increasing incidence of PTC in the recent years, the familial form of the disease has also become more common than previously reported and constitutes nearly 10% of all thyroid cancers. Many aspects of FNMTC are debated, concerning both clinical and genetic aspects. Several studies reported that, in comparison with sporadic PTCs, FPTCs are more aggressive at disease presentation, while other authors reported no differences in the clinical behavior of sporadic and familial PTCs. For this reason, recent guidelines do not recommend screening of family members of patients with diagnosis of differentiated thyroid cancer (DTC). FNMTC is described as a polygenic disorder associated with multiple low- to moderate-penetrance susceptibility genes and incomplete penetrance. At the moment, the genetic factors contributing to the development of FNMTC remain poorly understood, though many putative genes have been proposed in the recent years.

PURPOSE

Based on current literature and our experience with FNMTC, in this review, we critically discussed the most relevant controversies, including its definition, the genetic background and some clinical aspects as screening and treatment.

Genetics of Familial Non-Medullary Thyroid Carcinoma (FNMTC)

Non-medullary thyroid carcinoma (NMTC) is the most frequent endocrine tumor and originates from the follicular epithelial cells of the thyroid. Familial NMTC (FNMTC) has been defined in pedigrees where two or more first-degree relatives of the patient present the disease in absence of other predisposing environmental factors. Compared to sporadic cases, FNMTCs are often multifocal, recurring more frequently and showing an early age at onset with a worse outcome. FNMTC cases show a high degree of genetic heterogeneity, thus impairing the identification of the underlying molecular causes. Over the last two decades, many efforts in identifying the susceptibility genes in large pedigrees were carried out using linkage-based approaches and genome-wide association studies, leading to the identification of susceptibility loci and variants associated with NMTC risk. The introduction of next-generation sequencing technologies has greatly contributed to the elucidation of FNMTC predisposition, leading to the identification of novel candidate variants, shortening the time and cost of gene tests. In this review we report the most significant genes identified for the FNMTC predisposition. Integrating these new molecular findings in the clinical data of patients is fundamental for an early detection and the development of tailored therapies, in order to optimize patient management.

Mutation-specific non-canonical pathway of PTEN as a distinct therapeutic target for glioblastoma

PTEN is one of the most frequently altered tumor suppressor genes in malignant tumors. The dominant-negative effect of PTEN alteration suggests that the aberrant function of PTEN mutation might be more disastrous than deletion, the most frequent genomic event in glioblastoma (GBM). This study aimed to understand the functional properties of various PTEN missense mutations and to investigate their clinical relevance. The genomic landscape of PTEN alteration was analyzed using the Samsung Medical Center GBM cohort and validated via The Cancer Genome Atlas dataset. Several hotspot mutations were identified, and their subcellular distributions and phenotypes were evaluated. We established a library of cancer cell lines that overexpress these mutant proteins using the U87MG and patient-derived cell models lacking functional PTEN. PTEN mutations were categorized into two major subsets: missense mutations in the phosphatase domain and truncal mutations in the C2 domain. We determined the subcellular compartmentalization of four mutant proteins (H93Y, C124S, R130Q, and R173C) from the former group and found that they had distinct localizations; those associated with invasive phenotypes ('edge mutations') localized to the cell periphery, while the R173C mutant localized to the nucleus. Invasive phenotypes derived from edge substitutions were unaffected by an anti-PI3K/Akt agent but were disrupted by microtubule inhibitors. PTEN mutations exhibit distinct functional properties regarding their subcellular localization. Further, some missense mutations ('edge mutations') in the phosphatase domain caused enhanced invasiveness associated with dysfunctional cytoskeletal assembly, thus suggesting it to be a potent therapeutic target.

From BRCA1 to Polygenic Risk Scores: Mutation-Associated Risks in Breast Cancer-Related Genes

Background

There has been huge progress over the last 30 years in identifying the familial component of breast cancer.

Summary

Currently around 20% is explained by the high-risk genes BRCA1 and BRCA2, a further 2% by other high-penetrance genes, and around 5% by the moderate risk genes ATM and CHEK2. In contrast, the more than 300 low-penetrance single-nucleotide polymorphisms (SNP) now account for around 28% and they are predicted to account for most of the remaining 45% yet to be found. Even for high-risk genes which confer a 40-90% risk of breast cancer, these SNP can substantially affect the level of breast cancer risk. Indeed, the strength of family history and hormonal and reproductive factors is very important in assessing risk even for a BRCA carrier. The risks of contralateral breast cancer are also affected by SNP as well as by the presence of high or moderate risk genes. Genetic testing using gene panels is now commonplace.

Key-Messages

There is a need for a more parsimonious approach to panels only testing those genes with a definite 2-fold increased risk and only testing those genes with challenging management implications, such as CDH1 and TP53, when there is strong clinical indication to do so. Testing of SNP alongside genes is likely to provide a more accurate risk assessment.

PTENε suppresses tumor metastasis through regulation of filopodia formation

PTEN is one of the most frequently mutated genes in malignancies and acts as a powerful tumor suppressor. Tumorigenesis is involved in multiple and complex processes including initiation, invasion, and metastasis. The complexity of PTEN function is partially attributed to PTEN family members such as PTENα and PTENβ. Here, we report the identification of PTENε (also named as PTEN5), a novel N‐terminal‐extended PTEN isoform that suppresses tumor invasion and metastasis. We show that the translation of PTENε/PTEN5 is initiated from the CUG⁸¹⁶ codon within the 5′UTR region of PTEN mRNA. PTENε/PTEN5 mainly localizes in the cell membrane and physically associates with and dephosphorylates VASP and ACTR2, which govern filopodia formation and cell motility. We found that endogenous depletion of PTENε/PTEN5 promotes filopodia formation and enhances the metastasis capacity of tumor cells. Overall, we identify a new isoform of PTEN with distinct subcellular localization and molecular function compared to the known members of the PTEN family. These findings advance our current understanding of the importance and diversity of PTEN functions.

PTEN dephosphorylates Abi1 to promote epithelial morphogenesis

The tumor suppressor PTEN is essential for early development. Its lipid phosphatase activity converts PIP₃ to PIP₂ and antagonizes the PI3K–Akt pathway. In this study, we demonstrate that PTEN’s protein phosphatase activity is required for epiblast epithelial differentiation and polarization. This is accomplished by reconstitution of PTEN-null embryoid bodies with PTEN mutants that lack only PTEN’s lipid phosphatase activity or both PTEN’s lipid and protein phosphatase activities. Phosphotyrosine antibody immunoprecipitation and mass spectrometry were used to identify Abi1, a core component of the WASP-family verprolin homologous protein (WAVE) regulatory complex (WRC), as a new PTEN substrate. We demonstrate that PTEN dephosphorylation of Abi1 at Y213 and S216 results in Abi1 degradation through the calpain pathway. This leads to down-regulation of the WRC and reorganization of the actin cytoskeleton. The latter is critical to the transformation of nonpolar pluripotent stem cells into the polarized epiblast epithelium. Our findings establish a link between PTEN and WAVE-Arp2/3–regulated actin cytoskeletal dynamics in epithelial morphogenesis.

Recent advances in PTEN signalling axes in cancer

In over two decades since the discovery of phosphatase and tensin homologue deleted on chromosome 10 (PTEN), nearly 18,000 publications have attempted to elucidate its functions and roles in normal physiology and disease. The frequent disruption of PTEN in cancer cells was a strong indication that it had critical roles in tumour suppression. Germline PTEN mutations have been identified in patients with heterogeneous tumour syndromic diseases, known as PTEN hamartoma tumour syndrome (PHTS), and in some individuals with autism spectrum disorders (ASD). Today we know that by limiting oncogenic signalling through the phosphoinositide 3-kinase (PI3K) pathway, PTEN governs a number of processes including survival, proliferation, energy metabolism, and cellular architecture. Some of the most exciting recent advances in the understanding of PTEN biology and signalling have revisited its unappreciated roles as a protein phosphatase, identified non-enzymatic scaffold functions, and unravelled its nuclear function. These discoveries are certain to provide a new perspective on its full tumour suppressor potential, and knowledge from this work will lead to new anti-cancer strategies that exploit PTEN biology. In this review, we will highlight some outstanding questions and some of the very latest advances in the understanding of the tumour suppressor PTEN.

E3 ubiquitin ligase RNF126 affects bladder cancer progression through regulation of PTEN stability

E3 ubiquitin ligase RNF126 (ring finger protein 126) is highly expressed in various cancers and strongly associated with tumorigenesis. However, its specific function in bladder cancer (BCa) is still debatable. Here, we found that RNF126 was significantly upregulated in BCa tissue by TCGA database, and our studies indicated that downregulation of RNF126 significantly inhibited cell proliferation and metastasis through the EGFR/PI3K/AKT signaling pathway in BCa cells. Furthermore, we identified PTEN, an inhibitor of the PI3K/AKT signaling pathway, as a novel substrate for RNF126. By co-immunoprecipitation assays, we proved that RNF126 directly interacts with PTEN. Predominantly, PTEN binds to the C-terminal containing the RING domain of RNF126. The in vivo ubiquitination assay showed that RNF126 specifically regulates PTEN stability through poly-ubiquitination. Furthermore, PTEN knockdown restored cell proliferation, metastasis, and tumor formation of BCa cells inhibited by RNF126 silencing in vitro and in vivo. In conclusion, these results identified RNF126 as an oncogene that functions through ubiquitination and degradation of PTEN in BCa.

Cell Populations Expressing Stemness-Associated Markers in Vascular Anomalies

Treatment of vascular anomalies (VAs) is mostly empirical and, in many instances unsatisfactory, as the pathogeneses of these heterogeneous conditions remain largely unknown. There is emerging evidence of the presence of cell populations expressing stemness-associated markers within many types of vascular tumors and vascular malformations. The presence of these populations in VAs is supported, in part, by the observed clinical effect of the mTOR inhibitor, sirolimus, that regulates differentiation of embryonic stem cells (ESCs). The discovery of the central role of the renin-angiotensin system (RAS) in regulating stem cells in infantile hemangioma (IH) provides a plausible explanation for its spontaneous and accelerated involution induced by β-blockers and ACE inhibitors. Recent work on targeting IH stem cells by inhibiting the transcription factor SOX18 using the stereoisomer R(+) propranolol, independent of β-adrenergic blockade, opens up exciting opportunities for novel treatment of IH without the β-adrenergic blockade-related side effects. Gene mutations have been identified in several VAs, involving mainly the PI3K/AKT/mTOR and/or the Ras/RAF/MEK/ERK pathways. Existing cancer therapies that target these pathways engenders the exciting possibility of repurposing these agents for challenging VAs, with early results demonstrating clinical efficacy. However, there are several shortcomings with this approach, including the treatment cost, side effects, emergence of treatment resistance and unknown long-term effects in young patients. The presence of populations expressing stemness-associated markers, including transcription factors involved in the generation of induced pluripotent stem cells (iPSCs), in different types of VAs, suggests the possible role of stem cell pathways in their pathogenesis. Components of the RAS are expressed by cell populations expressing stemness-associated markers in different types of VAs. The gene mutations affecting the PI3K/AKT/mTOR and/or the Ras/RAF/MEK/ERK pathways interact with different components of the RAS, which may influence cell populations expressing stemness-associated markers within VAs. The potential of targeting these populations by manipulating the RAS using repurposed, low-cost and commonly available oral medications, warrants further investigation. This review presents the accumulating evidence demonstrating the presence of stemness-associated markers in VAs, their expression of the RAS, and their interaction with gene mutations affecting the PI3K/AKT/mTOR and/or the Ras/RAF/MEK/ERK pathways, in the pathogenesis of VAs.

Colorectal polyposis as a clue to the diagnosis of Cowden syndrome: Report of two cases and literature review

Cowden Syndrome (CS) is an autosomal dominant disorder characterized by hamartomatous growth in several organs and by an increased risk of malignancies, which makes its recognition essential to undertake risk reduction measures. Although the involvement of gastrointestinal tract is extremely common, awareness of this entity among gastroenterologists appears limited. We report on two unrelated patients: a 46-year-old male and a 38-year-old woman, who were referred to the Genetic Clinic because of the endoscopic finding of multiple colorectal polyps. Despite both displayed striking clinical (and, in the first case, familial) manifestations of Cowden Syndrome (PTEN Hamartoma Tumor Syndrome-PHTS), they had not been recognized before. Diagnosis of PHTS was confirmed by the detection of causative PTEN variants. Pathological examination of the polyps showed multiple histology types: hyperplastic, juvenile, serrated and lymphoid. Hyperplastic polyps analyzed from both patients failed to show BRAF V600E and KRAS codon 12/13 mutations, which provides evidence against their potential to evolve to colorectal cancer through the serrated pathway. We then reviewed the literature on gastrointestinal polyps detected in patients with Cowden Syndrome, in order to provide a comprehensive scenario of presentations: among a total of 568 patients reported in the literature, 91.7 % presented with colon polyps, with 63.0 % having two or more different histological types of polyps; besides, 58.5 % had extra-colonic polyps (located either in stomach and/or in small intestine). Finding multiple polyps with mixed and/or unusual histology should alert gastroenterologists and pathologists about the possible diagnosis of Cowden Syndrome and prompt the search for other manifestations of this condition in the patient.

Rare case of apatinib acquired resistance induced by point mutation of WRN p.V697F through activation of the PI3K/AKT apoptosis-inhibiting pathway

Targeted therapy has become the main treatment for non-small cell lung cancer (NSCLC). Apatinib is a new antiangiogenic antitumor drug developed in China which targets vascular endothelial growth factor receptor-2 (VEGFR-2). We recently treated a 50-year-old female patient who underwent a bronchoscopic biopsy and was subsequently pathologically diagnosed with squamous cell carcinoma of NSCLC. EML4-ALK and MINPP1 & PAPSS2-PTEN fusions were found to be present in tumor tissue and blood. Sequential targeted therapy was commenced with gemcitabine + cisplatin, docetaxel, tegafur, gimeracil, oteracil potassium capsules + carboplatin, and other third-line chemotherapy involving antineoplastic therapy, but unfortunately the patient showed primary drug resistance to this treatment regimen. Crizotinib was administered but was found to be ineffective. After two months of treatment, the disease had progressed and next generation sequencing (NGS) was subsequently performed. Apatinib was administered thereafter and the patient's symptoms improved after one week. Following administration for one month, CT scan revealed that the primary lung tumor lesions were significantly necrotic and they were narrowed. The patient's symptoms of coughing, phlegm production, and wheezing had also reduced. Her lung disease was under stable control 2.5 months later, but abdominal CT unfortunately revealed a suspected new nidus in the liver. A third gene mutation detection test showed that ALK and PTEN genetic mutations were obviously decreased; however, the patient was found to have developed WRN p.V697F (c.G2089T) point mutation, which was a new gene mutation. We suspected that the WRN gene mutation had led to apatinib resistance. We determined the absolute position of this point mutation to be chr8:30969131 with a transcript number of NM_000553.4. We retrieved information on human somatic cells from the ExAC, 1000 Genomes Browser, ESP database and PubMed databases. All the results indicated that the mutation identified in this study has not been previously reported worldwide.

PTEN and Other PtdIns(3,4,5)P3 Lipid Phosphatases in Breast Cancer

The phosphoinositide 3-kinase (PI3K)/AKT signalling pathway is hyperactivated in ~70% of breast cancers. Class I PI3K generates PtdIns(3,4,5)P₃ at the plasma membrane in response to growth factor stimulation, leading to AKT activation to drive cell proliferation, survival and migration. PTEN negatively regulates PI3K/AKT signalling by dephosphorylating PtdIns(3,4,5)P₃ to form PtdIns(4,5)P₂. PtdIns(3,4,5)P₃ can also be hydrolysed by the inositol polyphosphate 5-phosphatases (5-phosphatases) to produce PtdIns(3,4)P₂. Interestingly, while PTEN is a bona fide tumour suppressor and is frequently mutated/lost in breast cancer, 5-phosphatases such as PIPP, SHIP2 and SYNJ2, have demonstrated more diverse roles in regulating mammary tumourigenesis. Reduced PIPP expression is associated with triple negative breast cancers and reduced relapse-free and overall survival. Although PIPP depletion enhances AKT phosphorylation and supports tumour growth, this also inhibits cell migration and metastasis in vivo, in a breast cancer oncogene-driven murine model. Paradoxically, SHIP2 and SYNJ2 are increased in primary breast tumours, which correlates with invasive disease and reduced survival. SHIP2 or SYNJ2 overexpression promotes breast tumourigenesis via AKT-dependent and independent mechanisms. This review will discuss how PTEN, PIPP, SHIP2 and SYNJ2 distinctly regulate multiple functional targets, and the mechanisms by which dysregulation of these distinct phosphoinositide phosphatases differentially affect breast cancer progression.

Invasive apocrine carcinoma of the breast: clinicopathologic features and comprehensive genomic profiling of 18 pure triple-negative apocrine carcinomas

Pure invasive apocrine carcinoma is a rare type of primary breast cancer, constituting ~1% of all breast cancers. Since most pure invasive apocrine carcinomas are triple negative, the lack of targeted therapies for triple-negative breast cancer has fostered efforts to discover actionable molecular targets in these tumors. In this study, we analyzed the clinicopathologic characteristics and comprehensive genomic profiling of 18 patients with pure triple-negative apocrine carcinomas (TNACs) using a 324-gene panel assay (FoundationOne CDx). The median age of these patients was 55.5 years, and the postmenopausal status rate was 77.8%. In total, 83.3% of patients were diagnosed with histological grade II, and 16.7% were diagnosed with grade III. The majority of patients presented at an early tumor-node-metastasis (TNM) stage (I: 38.9%; II: 50.0%; and III: 11.1%). The mean Ki-67 index was 9.7%, and the percent of PD-L1 positivity was 11.7%. With a median follow-up period of 76.5 months, one patient died, and two experienced distant metastases. There were 61 clinically relevant genomic alterations among all 18 pure TNACs, and the mean tumor mutation burden (TMB) was 3 Mut/Mb. The top ranked altered genes were PIK3CA (72.2%), PTEN (33.3%) and TP53 (27.8%). There were four novel mutations found in PTEN and an actionable rearrangement involving FGFR2-TACC2 that has not been reported in breast cancer before. In total, 88.9%, 50%, 44.4%, and 16.7% of TNACs had at least one clinically relevant genomic alteration in genes involved in the PI3K/mTOR, cell cycle, RAS/RAF/MEK and growth factor receptor-related pathways, respectively. All patients had at least one clinically relevant genomic alteration, and 94.4% had at least one actionable alteration. To the best of our knowledge, this study is the largest genomic sequencing cohort of pure TNACs. Incorporation of comprehensive genomic profiling into TNACs might shed light on potential therapeutic opportunities for both targeted drugs and immune checkpoint inhibitors.

Clinicopathological and Molecular Characteristics of Pleomorphic Invasive Lobular Carcinoma

Pleomorphic invasive lobular carcinoma (PILC) is a distinct morphological and biologically aggressive variant of invasive lobular carcinoma (ILC). We hypothesized that was due to de novo activation of PI3K/Akt/mTOR pathway in PILC resulting in higher proliferation rate and markers of cell cycle activation. We identified PILC and ILC tumors and tested for PI3K/Akt/mTOR pathway activation by immunohistochemistry (PTEN and pS6K1) and gene expression analysis (by Nanostring nCounter system). Proliferation index (Ki67) was elevated in 85% of PILCs compared to 20% of ILCs (p < 0.007). PTEN expression was high in all while pS6K1 was high in 8/9 PILCs compared to 3/9 ILCs (p < 0.007). Gene expression analysis shows that PILCs have overexpression of genes involved in cell cycle proliferation, cellular proliferation, DNA damage, and repair genes but no difference in PI3K/Akt/mTOR pathway genes. PILCs are a biologically distinct group of ILC, and clinicopathological characteristics suggest they would have a more clinically aggressive behavior. In addition, our results indicate that PI3k/Akt/mTOR pathway and cell cycle proliferation are activated in majority of these tumors. Further studies are needed to investigate these mechanisms as there are approved therapies available that may benefit PILCs.

In vitro activation of ovarian cortex and autologous transplantation: A novel approach to primary ovarian insufficiency and diminished ovarian reserve

BACKGROUND

Primary ovarian insufficiency (POI) and diminished ovarian reserve are two conditions that affect women’s fertility. Oocyte donation remains an option for these patients; however, the development of certain novel technologies, such as in vitro activation of ovarian cortex (IVA), enables the possibility of activating the pool of resting primordial follicles, increasing the chance of pregnancy.

OBJECTIVE AND RATIONALE

Here, we review the main pathways (PI3K and Hippo signaling) that govern the activation of primordial follicles and its application through the development of culture systems that support ovarian cortex for autologous transplantation. We also review the available data from case reports regarding outcomes of pregnancy and live birth rates with IVA.

SEARCH METHODS

A PubMed search was conducted using the PubMed-NCBI database to identify literature pertinent to the pathways involved in the activation of primordial follicles and the outcomes of IVA techniques from 2013 to the present.

OUTCOMES

Women with POI have around a 5% chance of spontaneous pregnancy. Recently, novel techniques involving the activation of primordial follicles through molecular pathways have been developed, thus increasing the odds of these patients. More recently, the introduction of a drug-free IVA technique has shown to increase the number of antral follicles with successful oocyte maturation after gonadotropin treatment, reaching pregnancy rates over 30%, either through spontaneous conception or by the implementation of assisted reproductive technology.

LIMITATIONS

The evidence of this review is based on a few small series, so data should be interpreted with caution, and only randomized controlled trials could estimate the real magnitude and success of the procedure.

REASONS FOR CAUTION

IVA technique remains an experimental strategy, with limited available data and the requirement of invasive procedures. Moreover, possible carcinogenic effects not yet determined after transplantation require special caution.

WIDER IMPLICATIONS

In view of the results achieved, IVA could provide a promising option for the preservation of fertility in some cancer patients and prepuberal girls where the only alternative is tissue cryopreservation.

STUDY FUNDING/COMPETING INTERESTS

The authors received no specific funding for this work and declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Multiple Meningiomata in Cowden Syndrome

Cowden syndrome (CS) is a rare, congenital disease with associated cancers, but in a neurosurgical context is typically considered part of Lhermitte-Duclos. This misrepresentation is the likely cause of under-diagnosis. Furthermore, the presence of meningiomata has been described in CS patients but its absence as part of the condition's major criteria suggest the correlation requires greater documentation. A 41-year-old woman with multiple cancers and a familial circumambience of CS was reviewed in clinic where multiple meningiomata were incidentally identified on MRI. Despite a lack of neurological impairment, and the general reluctance in treating the meningiomas of congenital disease with radiotherapy (RT), the patient underwent stereotactic radio-surgery (SRS) and at one-year post-procedure has reported no side effects or toxicity.

Under-ascertainment of breast cancer susceptibility gene carriers in a cohort of New Zealand female breast cancer patients

BACKGROUND

Diagnostic screening for pathogenic variants in breast cancer susceptibility genes, including BRCA1, BRCA2, PALB2, PTEN and TP53, may be offered to New Zealanders from suspected high-risk breast (and ovarian) cancer families. However, it is unknown how many high-risk pathogenic variant carriers in New Zealand are not offered genetic screening using existing triage tools and guidelines for breast (and ovarian) cancer patients.

METHODS

Panel-gene sequencing of the coding and non-coding regions of the BRCA1 and BRCA2 genes, and the coding regions and splice sites of CDH1, PALB2, PTEN and TP53, was undertaken for an unselected cohort of 367 female breast cancer patients. A total of 1685 variants were evaluated using the ENIGMA and the ACMG/AMP variant classification guidelines.

RESULTS

Our study identified that 13 (3.5%) breast cancer patients carried a pathogenic or likely pathogenic variant in BRCA1, BRCA2, PALB2, or PTEN. A significantly higher number of pathogenic variant carriers had grade 3 tumours (10/13) when compared to non-carriers; however, no other clinicopathological characteristics were found to be significantly different between (likely) pathogenic variant carriers and non-carriers, nor between variant of unknown significance carriers and non-carriers. Notably, 46% of the identified (likely) pathogenic variant carriers had not been referred for a genetic assessment and consideration of genetic testing.

CONCLUSION

Our study shows a potential under-ascertainment of women carrying a (likely) pathogenic variant in a high-risk breast cancer susceptibility gene. These results suggest that further research into testing pathways for New Zealand breast cancer patients may be required to reduce the impact of hereditary cancer syndromes for these individuals and their families.

Dermal hyperneury

Dermal hyperneury (DN) is a rarely reported form of small nerve hypertrophy characterized by an exaggerated size and prominence of dermal nerve fibers. Clinically, it can present with or without visible lesions, within a syndrome or sporadically, and in solitary or multiple fashion. The syndromes most commonly associated with DN include multiple endocrine neoplasia 2B and 2A, neurofibromatosis type II, and Cowden syndrome. Patients with syndrome-associated DN have an increased risk for various malignancies. Sporadic DN has been reported either in association with cutaneous tumors/reactive lesions, such as nodular prurigo, or in idiopathic form, where it can present with multiple DN lesions. There is a morphologic overlap between mucocutaneous neuromas and DN, as the former can have the appearance of either bulkier circumscribed lesions or tortuous and hyperplastic nerves more akin to DN. Epithelial sheath neuroma also shares a similar appearance to DN, from which it can be distinguished by a squamoid-appearing and thickened perineurium.

PTEN in Regulating Hematopoiesis and Leukemogenesis

PTEN is one of the most frequently mutated tumor suppressor genes in human cancers. By counteracting the PI3K/AKT/mTOR pathway, PTEN plays an essential role in regulating hematopoietic stem cells (HSCs) self-renewal, migration, lineage commitment, and differentiation. PTEN also plays important roles in suppressing leukemogenesis, especially T-cell acute lymphoblastic leukemia (T-ALL). Herein, we will review the function of PTEN in regulating hematopoiesis and leukemogenesis and discuss potential therapeutic approaches against leukemia with PTEN mutations.

Early-onset renal cell carcinoma in PTEN harmatoma tumour syndrome

Individuals with PTEN hamartoma tumour syndrome (PHTS), including Cowden syndrome (CS), are susceptible to multiple benign hamartomas and an increased risk of cancer, particularly breast, endometrial, and thyroid. As a result, individuals undergo enhanced surveillance for early detection of these cancers. However, less commonly occurring cancers, such as colorectal and kidney, have insufficient guidelines for early detection. Currently, screening for kidney cancer via renal ultrasound begins at 40 years of age, because there were only rare cases of elevated risk in prospective series under 40. There have, however, been accumulating reports of kidney cancer in individuals with CS in their 30s, illustrating a need to lower the age of surveillance. We present additional evidence of renal cell carcinoma in two individuals with CS in their early twenties, and propose a reassessment of the abdominal surveillance in patients with PHTS. We propose biannual screening for kidney cancer beginning at 20 years of age.

Genetic Susceptibility to Endometrial Cancer: Risk Factors and Clinical Management

Endometrial cancer (EC) is the most common cancer affecting the female reproductive organs in higher-income states. Apart from reproductive factors and excess weight, genetic predisposition is increasingly recognized as a major factor in endometrial cancer risk. Endometrial cancer is genetically heterogeneous: while a subgroup of patients belongs to cancer predisposition syndromes (most notably the Lynch Syndrome) with high to intermediate lifetime risks, there are also several common genomic polymorphisms contributing to the spectrum of germline predispositions. Germline variants and somatic events may act in concert to modulate the molecular evolution of the tumor, where mismatch-repair deficiency is common in endometrioid endometrial tumors whereas homologous recombinational repair deficiency has been described for non-endometrioid endometrial tumors. In this review, we will survey the currently known genomic predispositions for endometrial cancer and discuss their relevance for clinical management in terms of counseling, screening and novel treatments.

Germline PTEN mutations are associated with a skewed peripheral immune repertoire in humans and mice

Individuals with germline mutations in the gene encoding phosphatase and tensin homolog on chromosome ten (PTEN) are diagnosed with PTEN hamartoma tumor syndrome (PHTS) and are at high risk for developing breast, thyroid and other cancers and/or autoimmunity or neurodevelopmental issues including autism spectrum disorders. Although well recognized as a tumor suppressor, involvement of PTEN mutations in mediating such a diverse range of phenotypes indicates a more central involvement for PTEN in immunity than previously recognized. To address this, sequencing of the T-cell receptor variable-region β-chain was performed on peripheral blood from PHTS patients. Based on patient findings, we performed mechanistic studies in two Pten knock-in murine models, distinct from each other in cell compartment-specific predominance of Pten. We found that PTEN mutations in humans and mice are associated with a skewed T- and B-cell gene repertoire, characterized by increased prevalence of high-frequency clones. Immunological characterization showed that Pten mutants have increased B-cell proliferation and a proclivity towards increased T-cell reactivity upon Toll-like-receptor stimulation. Furthermore, decreases in nuclear but not cytoplasmic Pten levels associated with a reduction in expression of the autoimmune regulator (Aire), a critical mediator of central immune tolerance. Mechanistically, we show that nuclear PTEN most likely regulates Aire expression via its emerging role in splicing regulation. We conclude that germline disruption of PTEN, both in human and mouse, results in compromised central immune tolerance processes that may significantly impact individual stress responses and therefore predisposition to autoimmunity and cancer.

Molecular Markers Guiding Thyroid Cancer Management

The incidence of thyroid cancer is rapidly increasing, mostly due to the overdiagnosis and overtreatment of differentiated thyroid cancer (TC). The increasing use of potent preclinical models, high throughput molecular technologies, and gene expression microarrays have provided a deeper understanding of molecular characteristics in cancer. Hence, molecular markers have become a potent tool also in TC management to distinguish benign from malignant lesions, predict aggressive biology, prognosis, recurrence, as well as for identification of novel therapeutic targets. In differentiated TC, molecular markers are mainly used as an adjunct to guide management of indeterminate nodules on fine needle aspiration biopsies. In contrast, in advanced thyroid cancer, molecular markers enable targeted treatments of affected signalling pathways. Identification of the driver mutation of targetable kinases in advanced TC can select treatment with mutation targeted tyrosine kinase inhibitors (TKI) to slow growth and reverse adverse effects of the mutations, when traditional treatments fail. This review will outline the molecular landscape and discuss the impact of molecular markers on diagnosis, surveillance and treatment of differentiated, poorly differentiated and anaplastic follicular TC.

Discovery of the PTEN Tumor Suppressor and Its Connection to the PI3K and AKT Oncogenes

PTEN (phosphatase and tensin homolog on chromosome 10) was discovered over 20 years ago in 1997 and linked to the phosphatidylinositol 3-kinase (PI3K) and AKT oncogenes the following year. The discovery of PTEN emerged from the linked concepts of oncogenes and tumor suppressor genes that cause and prevent cancer and the fields of tumor viruses and human cancer genetics from which these two concepts arose. While much has been learned since, the initial discovery and characterization, including the discovery that PTEN is a regulator of PI3K and AKT, provide the foundation on which we continue to build our knowledge. To provide the context in which these cancer genes were discovered, background information that led to their discovery will also be discussed, which will hopefully be a useful guide for readers seeking to build on the work of others.

FAM35A/SHLD2/RINN2: A novel determinant of double strand break repair pathway choice and genome stability in cancer

FAM35A, alternatively known as SHLD2 and RINN2, was recently characterized as a DNA repair gene, evolutionarily conserved in higher vertebrates. FAM35A is a 53BP1-pathway factor and a component of the Shieldin/RINN complex. Among 53BP1-pathway factors, FAM35A has unique domains: an N-terminal disordered domain and three C-terminal OB-fold domains. These C-terminal domains have homology with the OB-fold domains of the single-stranded DNA binding protein, RPA1. With other 53BP1-pathway factors, FAM35A inhibits DNA end resection. FAM35A defective cell lines are sensitive to DNA double-strand break inducing agents. Concurrent FAM35A and BRCA1 defects in mammalian cell lines cause resistance to PARP inhibitors and camptothecin. The clinical relevance of this interaction is still unknown, but cancer genomics databases indicate that FAM35A is deleted in 6-13% of prostate cancers and in at least one triple negative breast cancer patient-derived BRCA1 defective cell line. From meta-analysis, FAM35A overexpression in patients with triple negative and basal-like breast cancers is associated with poor survival compared to patients with low expression. From this evidence, clarification of FAM35A's function and the related mechanism of chemoresistance is likely to have clinical implications.

The duality of human oncoproteins: drivers of cancer and congenital disorders

Human oncoproteins promote transformation of cells into tumours by dysregulating the signalling pathways that are involved in cell growth, proliferation and death. Although oncoproteins were discovered many years ago and have been widely studied in the context of cancer, the recent use of high-throughput sequencing techniques has led to the identification of cancer-associated mutations in other conditions, including many congenital disorders. These syndromes offer an opportunity to study oncoprotein signalling and its biology in the absence of additional driver or passenger mutations, as a result of their monogenic nature. Moreover, their expression in multiple tissue lineages provides insight into the biology of the proto-oncoprotein at the physiological level, in both transformed and unaffected tissues. Given the recent paradigm shift in regard to how oncoproteins promote transformation, we review the fundamentals of genetics, signalling and pathogenesis underlying oncoprotein duality.

Regulating tumor suppressor genes: post-translational modifications

Tumor suppressor genes cooperate with each other in tumors. Three important tumor suppressor proteins, retinoblastoma (Rb), p53, phosphatase, and tensin homolog deleted on chromosome ten (PTEN) are functionally associated and they regulated by post-translational modification (PTMs) as well. PTMs include phosphorylation, SUMOylation, acetylation, and other novel modifications becoming growing appreciated. Because most of PTMs are reversible, normal cells use them as a switch to control the state of cells being the resting or proliferating, and PTMs also involve in cell survival and cell cycle, which may lead to abnormal proliferation and tumorigenesis. Although a lot of studies focus on the importance of each kind of PTM, further discoveries shows that tumor suppressor genes (TSGs) form a complex "network" by the interaction of modification. Recently, there are several promising strategies for TSGs for they change more frequently than carcinogenic genes in cancers. We here review the necessity, characteristics, and mechanisms of each kind of post-translational modification on Rb, p53, PTEN, and its influence on the precise and selective function. We also discuss the current antitumoral therapies of Rb, p53 and PTEN as predictive, prognostic, and therapeutic target in cancer.

Resveratrol potentiates the anti-tumor effects of rapamycin in papillary thyroid cancer: PI3K/AKT/mTOR pathway involved

The phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway plays an important role in the development of papillary thyroid cancer. While rapamycin has been shown to exhibit anti-tumor effects, it may also activate AKT, resulting in increased cell survival and drug resistance, thereby limiting its anti-tumor effects. Resveratrol can also inhibit tumor growth by regulating the PI3K/AKT/mTOR signaling pathway. The present study investigated the anti-tumor effects of the combined use of rapamycin and resveratrol in papillary thyroid cancer. We first treated two human papillary thyroid cancer cell lines (KTC-1 and TPC-1) with single or combined administration, and examined the effects on proliferation, the cell cycle, apoptosis, and invasion/migration of papillary thyroid cancer cells. A mouse xenograft model was induced with KTC-1 and TPC-1 cells followed by treatment with single or combined administration. Body weight and tumor size were monitored to assess the toxicity of each compound. The phosphorylation of AKT and the mTORC1 target p70S6 kinase (p70S6K) in tumors was also examined. Both rapamycin and resveratrol inhibited proliferation, altered the cell cycle, and induced apoptosis of papillary thyroid cancer cells. Invasion and migration were also reduced, as was the tumor growth rate in the xenograft model. Co-administration significantly enhanced the anti-tumor effects than use of any one drug, and significantly reduced the phosphorylation of AKT and p70S6K compared to treatment with rapamycin alone. Overall, compared to single use of rapamycin or resveratrol, co-administration had a synergistic effect in inhibiting proliferation and invasion/migration of papillary thyroid cancer cells and inducing apoptosis. Resveratrol is sensitizing the anti-tumor effects of rapamycin and the PI3K/AKT/mTOR signaling is involved. Although further animal and clinical studies are needed to clarify the mechanism and assess drug safety, the present study suggests that the combination of rapamycin and resveratrol may be a promising strategy for the treatment of papillary thyroid cancer.

An Integrated Deep-Mutational-Scanning Approach Provides Clinical Insights on PTEN Genotype-Phenotype Relationships

Germline variation in PTEN results in variable clinical presentations, including benign and malignant neoplasia and neurodevelopmental disorders. Despite decades of research, it remains unclear how the PTEN genotype is related to clinical outcomes. In this study, we combined two recent deep mutational scanning (DMS) datasets probing the effects of single amino acid variation on enzyme activity and steady-state cellular abundance with a large, well-curated clinical cohort of PTEN-variant carriers. We sought to connect variant-specific molecular phenotypes to the clinical outcomes of individuals with PTEN variants. We found that DMS data partially explain quantitative clinical traits, including head circumference and Cleveland Clinic (CC) score, which is a semiquantitative surrogate of disease burden. We built logistic regression models that use DMS and CADD scores to separate clinical PTEN variation from gnomAD control-only variation with high accuracy. By using a survival-like analysis, we identified molecular phenotype groups with differential risk of early cancer onset as well as lifetime risk of cancer. Finally, we identified classes of DMS-defined variants with significantly different risk levels for classical hamartoma-related features (odds ratio [OR] range of 4.1-102.9). In stark contrast, the risk for developing autism or developmental delay does not significantly change across variant classes (OR range of 5.4-12.4). Together, these findings highlight the potential impact of combining DMS datasets with rich clinical data and provide new insights that might guide personalized clinical decisions for PTEN-variant carriers.

Impact of vascular anomalies on the PTEN phenotype in children and young adults

Germline PTEN (phosphatase and tensin homolog) mutations lead to inappropriate cell survival and growth, and a predisposition to multiple cancers. Some patients also have vascular anomalies (VAs), and it is unclear whether these patients have different phenotypes or oncologic risks. We conducted a two-institution retrospective cohort study to better understand the phenotypes of children and young adults with PTEN mutations, and to compare individuals with VA to those without. Almost half of the patients had thyroid tumors and nearly one quarter developed gastrointestinal tumors before 30 years of age. The presence of VA was positively associated with bulky overgrowth but did not appear to modify oncologic risk.

Cowden syndrome complicated by schizophrenia: A first clinical report

Patients with Cowden syndrome exhibit mucocutaneous lesions, hamartomatous polyposis of the gastrointestinal tract, and macrocephaly, often complicated by malignant tumors, such as breast, thyroid, and uterine cancers. Autism spectrum and epilepsy have been known as neuropsychiatric symptoms associated with Cowden syndrome; however, to the best of our knowledge, there is no report on cases complicated by schizophrenia. Here, we report a first case of Cowden syndrome complicated by schizophrenia. A 49-year-old Japanese woman started experiencing auditory hallucinations in her teens. She had left breast cancer at the age of 34 years, and right breast cancer at the age of 37 years, all of which were surgically treated. She was also being treated by oral medications for Hashimoto's disease. On consulting her previous doctor for abnormal uterine bleeding that lasted for a year, she was diagnosed with endometrial cancer. However, immediately before surgery, her auditory hallucinations and paranoid delusions became severe, and she was referred to our hospital for detailed examination and treatment. No abnormalities were found on head MRI, and she was diagnosed with schizophrenia on the basis of neuropsychiatric examination findings. After her psychiatric symptoms were controlled by 2 mg of risperidone, she underwent surgery for endometrial cancer. Although there was no apparent family history, physical findings including macrocephaly and papillomatous skin lesions together with her past medical history of multiple malignant tumors suggested Cowden syndrome. Postoperatively, genetic testing revealed a pathogenic variant c.655C > T; p. Gln219* (NM_000314.4) in PTEN, leading to the confirmation of the diagnosis of Cowden syndrome.

Germline Mutation in MUS81 Resulting in Impaired Protein Stability is Associated with Familial Breast and Thyroid Cancer

Multiple primary thyroid cancer (TC) and breast cancer (BC) are commonly diagnosed, and the lifetime risk for these cancers is increased in patients with a positive family history of both TC and BC. Although this phenotype is partially explained by TP53 or PTEN mutations, a significant number of patients are negative for these alterations. We judiciously recruited patients diagnosed with BC and/or TC having a family history of these tumors and assessed their whole-exome sequencing. After variant prioritization, we selected MUS81 c.1292G>A (p.R431H) for further investigation. This variant was genotyped in a healthy population and sporadic BC/TC tissues and investigated at the protein level and cellular models. MUS81 c.1292G>A was the most frequent variant (25%) and the strongest candidate due to its function of double-strand break repair. This variant was confirmed in four relatives from two families. MUS81 p.R431H protein exhibited lower expression levels in tumors from patients positive for the germline variant, compared with wild-type BC, and normal breast and thyroid tissues. Using cell line models, we showed that c.1292G>A induced protein instability and affected DNA damage response. We suggest that MUS81 is a novel candidate involved in familial BC/TC based on its low frequency in healthy individuals and proven effect in protein stability.

Toward Systems Pathology for PTEN Diagnostics

Germline alterations of the tumor suppressor PTEN have been extensively characterized in patients with PTEN hamartoma tumor syndromes, encompassing subsets of Cowden syndrome, Bannayan-Riley-Ruvalcaba syndrome, Proteus and Proteus-like syndromes, as well as autism spectrum disorder. Studies have shown an increase in the risk of developing specific cancer types in the presence of a germline PTEN mutation. Furthermore, outside of the familial setting, somatic variants of PTEN occur in numerous malignancies. Here we introduce and discuss the prospect of moving toward a systems pathology approach for PTEN diagnostics, incorporating clinical and molecular pathology data with the goal of improving the clinical management of patients with a PTEN mutation. Detection of a germline PTEN mutation can inform cancer surveillance and in the case of somatic mutation, have value in predicting disease course. Given that PTEN functions in the PI3K/AKT/mTOR pathway, identification of a PTEN mutation may highlight new therapeutic opportunities and/or inform therapeutic choices.

Zebrafish pten Genes Play Relevant but Distinct Roles in Antiviral Immunity

The PTEN (phosphatase and TENsin homolog on chromosome 10) gene encodes a bifunctional phosphatase that acts as a tumor suppressor. However, PTEN has been implicated in different immune processes, including autophagy, inflammation, regulation of natural killer (NK) cell cytolytic activity and type I interferon responses. Unlike mammals, zebrafish possess two pten genes (ptena and ptenb). This study explores the involvement of both zebrafish pten genes in antiviral defense. Although ptena^−/− and ptenb^−/− larvae were more susceptible to Spring viremia of carp virus (SVCV), the viral replication rate was lower in the mutant larvae than in the wild-type larvae. We observed that both mutant lines showed alterations in the transcription of numerous genes, including those related to the type I interferon (IFN) system, cytolytic activity, autophagy and inflammation, and some of these genes were regulated in opposite ways depending on which pten gene was mutated. Even though the lower replication rate of SVCV could be associated with impaired autophagy in the mutant lines, the higher mortality observed in the ptena^−/− and ptenb^−/− larvae does not seem to be associated with an uncontrolled inflammatory response.

Bone tissue and mineral metabolism in hereditary endocrine tumors: clinical manifestations and genetic bases

Inherited endocrine tumors are neoplasms of endocrine cells, transmitted via autosomal dominant germinal mutations. They present in two different forms: non-syndromic (patient has a single affected endocrine organ during his/her lifetime) or syndromic forms (multiple tumors in endocrine and non-endocrine organs during his/her lifetime).In addition to their common tumoral manifestations, many of these diseases present clinical affection of bone tissues and/or mineral metabolism, both as secondary complications of primary tumors and as primary defects due to genetic mutation. To date, few studies have documented these bone complications, and there are no systematic reviews in this area.We present a revision of medical literature about skeletal and mineral metabolism affections in inherited endocrine tumor syndromes, and studies, in cells and animal models, investigating the direct role of some genes, whose mutations are responsible for the development of endocrine tumors, in the regulation of bone and mineral metabolism.