The prevalence of DICER1 pathogenic variation in population databases

Sertoli-Leydig tumor and DICER1 gene mutation: A case series and literature review

OBJECTIVE

Sertoli-Leydig cell tumors (SLCTs) are rare neoplasms occurring in young women with 60% associated with DICER1 mutations. This is only the second published case series of patients with SLCTs with associated DICER1 gene alterations. DICER1 syndrome is a rare inherited tumor-susceptibility syndrome affecting organs such as the ovaries. We use this case series to inform readers on this increasingly important condition in gynecology.

METHODS AND RESULTS

We present three young females presenting with secondary amenorrhoea, hirsutism, acne and in one case tonic-clonic seizures. All cases had high testosterone levels and an adnexal mass on ultrasound. Following surgical removal, pathology confirmed SLCTs and genetic testing followed. All three patients had DICER1 syndrome with two patients subsequently found to be related.

DISCUSSION

The prevalence of DICER1 syndrome in the population is estimated to be 1 in 10 000 with a spectrum of sex cord stromal tumors affecting young women. The associated pathological classifications and management. This paper describes the DICER1 gene and the associated tumor predisposition syndrome alongside a surveillance protocol for use in clinical practice. It promotes discussion over the importance of early clinical genetics involvement in sex-cord stromal tumors and the associated difficulties in counseling in a young patient population. Genetic testing and early detection are imperative for targeted surveillance of at-risk organs to be performed but despite this there is no international guidance. The cases highlight the psychological impact of tumors in young patients and provokes an ethical discussion over DICER1 gene's inclusion in preimplantation genetics.

CONCLUSIONS

DICER1 syndrome is a rare but increasingly important condition in pediatric and adolescent gynecology with a paucity of published data and case reports. This makes international consensus on management and surveillance difficult.

Atrophic changes in thyroid tumors are strong indicators of underlying DICER1 mutations: a bi-institutional genotype-phenotype correlation study

Somatic and biallelic DICER1 mutations are reported in subsets of thyroid tumors, supporting the role of this gene in thyroid tumor development. As recent studies have brought attention to macrofollicular patterns, atrophic changes, and papillary structures as being associated with DICER1 mutations, we sought to explore these observations in a bi-institutional cohort. A total of 61 thyroid lesions (54 tumors and 7 cases of thyroid follicular nodular disease; TFND), including 26 DICER1 mutated and 35 DICER1 wildtype controls were subjected to histological re-investigation and clinical follow-up. DICER1-mutated lesions showed a statistically significant association with younger age at surgery (29.2 ± 12.5 versus 51.3 ± 18.8, p = 0.0001), a predominant macrofollicular growth pattern (20/26 mutated cases versus 18/35 wildtype; p = 0.01) and atrophic changes (20/26 mutated cases versus 2/35 wildtype; p = 0.0001). Similar results were obtained when excluding TFND cases. We also present clinical and histological triaging criteria for DICER1 sequencing of thyroid lesions, which led to the identification of DICER1 variants in 16 out of 26 cases (62%) when followed. Among these, 3 out of 12 cases with available data were found to carry a constitutional DICER1 mutation. This observation suggests that the majority of DICER1 mutations are somatic-however implies that sequencing of constitutional tissues could be clinically motivated. We conclude that DICER1 mutations are amassed in younger patients with macrofollicular-patterned tumors and, most strikingly, atrophic changes. Given the rate of constitutional involvement, our findings could be of clinical value, allowing the pathologist to triage cases for genetic testing based on histological findings.

Prevalence of lung cysts in adolescents and adults with a germline DICER1 pathogenic/likely pathogenic variant: a report from the National Institutes of Health and International Pleuropulmonary Blastoma/DICER1 Registry

BACKGROUND

Pleuropulmonary blastoma (PPB), the hallmark tumour associated with DICER1-related tumour predisposition, is characterised by an age-related progression from a cystic lesion (type I) to a high-grade sarcoma with mixed cystic and solid features (type II) or purely solid lesion (type III). Not all cystic PPBs progress; type Ir (regressed), hypothesised to represent regressed or non-progressed type I PPB, is an air-filled, cystic lesion lacking a primitive sarcomatous component. This study aims to evaluate the prevalence of non-progressed lung cysts detected by CT scan in adolescents and adults with germline DICER1 pathogenic/likely pathogenic (P/LP) variants.

METHODS

Individuals were enrolled in the National Cancer Institute Natural History of DICER1 Syndrome study, the International PPB/DICER1 Registry and/or the International Ovarian and Testicular Stromal Tumor Registry. Individuals with a germline DICER1 P/LP variant with first chest CT at 12 years of age or older were selected for this analysis.

RESULTS

In the combined databases, 110 individuals with a germline DICER1 P/LP variant who underwent first chest CT at or after the age of 12 were identified. Cystic lung lesions were identified in 38% (42/110) with a total of 72 cystic lesions detected. No demographic differences were noted between those with lung cysts and those without lung cysts. Five cysts were resected with four centrally reviewed as type Ir PPB.

CONCLUSION

Lung cysts are common in adolescents and adults with germline DICER1 variation. Further study is needed to understand the mechanism of non-progression or regression of lung cysts in childhood to guide judicious intervention.

A genome-first approach to characterize DICER1 pathogenic variant prevalence, penetrance and cancer, thyroid, and other phenotypes in 2 population-scale cohorts

Purpose

Population-scale, exome-sequenced cohorts with linked electronic health records (EHR) permit genome-first exploration of phenotype. Phenotype and cancer risk are well-characterized in children with a pathogenic DICER1 (HGNC ID:17098) variant. Here, the prevalence, penetrance and phenotype of pathogenic germline DICER1 variants in adults was investigated in two population-scale cohorts.

Methods

Variant pathogenicity was classified using published DICER1 ClinGen criteria in the UK Biobank (469,787 exomes; unrelated: 437,663) and Geisinger (170,503 exomes; unrelated: 109,789) cohorts. In the UK Biobank cohort, cancer diagnoses in the EHR, cancer and death registry were queried. For the Geisinger cohort, the Geisinger Cancer Registry and EHR were queried.

Results

In the UK Biobank, there were 46 unique pathogenic DICER1 variants in 57 individuals (1:8,242;95%CI:1:6,362-1:10,677). In Geisinger, there were 16 unique pathogenic DICER1 variants (including one microdeletion) in 21 individuals (1:8,119;95%CI:1:5,310-1:12,412). Cohorts were well-powered to find larger effect sizes for common cancers. Cancers were not significantly enriched in DICER1 heterozygotes; however, there was a ~4-fold increased risk for thyroid disease in both cohorts. There were multiple ICD10 codes enriched >2-fold in both cohorts.

Conclusion

Estimates of pathogenic germline DICER1 prevalence, thyroid disease penetrance and cancer phenotype from genomically ascertained adults are determined in two large cohorts.

Ultrasound-Histopathological Presentation of Thyroid and Ovary Lesions in Adolescent Patients with DICER1 Syndrome: Case Reports and Literature Overview

BACKGROUND

DICER1, a cancer predisposition syndrome (CPS), seems to escape timely diagnosis in pediatric patients. Case report 1: A 16-year-old female patient was referred to the endocrinology ward due to a large goiter. Her medical history indicated normal sexual maturation, with menarche occurring at 13.5 years. Over the past 2.5 years, she had developed pronounced androgenic symptoms, including a deepened male voice; facial, back, and neckline acne; hirsutism; and menstrual irregularities leading to secondary amenorrhea. A thyroid ultrasound identified a multinodular goiter (MNG) with cystic-solid lesions containing calcifications. An abdominal ultrasound identified a 5.7 × 6.9 cm solid mass in the right adnexal region, displacing the uterus to the left. Histopathological examination confirmed a Sertoli-Leydig cell tumor. The patient was subjected to a total thyroidectomy. Histopathology revealed benign follicular cell-derived neoplasms. Thyroid follicular nodular disease (TFND) was diagnosed bilaterally. DNA analysis using NGS, confirmed via the Sanger method, revealed a pathogenic heterozygotic variant c.2953C>T [p.Gln985*] in exon 18 of the DICER1 gene. Case report 2: A 12-year-old male patient was admitted to the pediatric surgery unit due to a 33 mL goiter. A month prior to his admission, the patient discovered a palpable nodule in his neck, accompanied by hoarseness. An ultrasound revealed MNG. Molecular analysis revealed a pathogenic heterozygotic variant c.2782C>T [p.Gln928*] in exon 17 of the DICER1 gene. Subsequently, a total thyroidectomy was performed, and histopathological examination revealed TFND bilaterally.

CONCLUSIONS

Recent advances in genetic evaluation and in histological approaches indicate that MNG/TFND, although rare in the pediatric population, when accompanied by characteristic ultrasound and histopathological features, and by additional features such as androgenization, may warrant assessment also of the DICER1 gene within CPS molecular panel screening.

Prevalence of DICER1 variants in large multinodular goiter: thyroid function, clinical and imaging characteristics

Objective

Mutations in DICER1 are found in differentiated thyroid carcinoma (DTC) and in multinodular goiter (MNG) at a younger age with other tumors, which characterizes DICER1 syndrome. DICER1 is one driver to DTC; however, it is also found in benign nodules. We speculated that patients with mutations in DICER1 may present long-lasting MNG. Our aim was to investigate the frequency of DICER1 variants in patients with MNG.

Subjects and methods

Patients who submitted to total thyroidectomy due to large MNG with symptoms were evaluated. DICER1 hotspots were sequenced from thyroid nodule samples. To confirm somatic mutation, DNA from peripheral blood was also analyzed.

Results

Among 715 patients, 154 were evaluated with 56.2 ± 12.3 years old (28-79) and the thyroid volume was 115.7 ± 108 mL (16.2-730). We found 11% with six DICER1 variations in a homo or heterozygous state. Only rs12018992 was a somatic DICER1 variant. All remaining variants were synonymous and likely benign, according to the ClinVar database. The rs12018992 was previously described in an adolescent with DTC, measuring 13 mm. There were no significant differences according to gender, familial history of goiter, age, thyroid volume, TSH and TI-RADS classification between DICER1 carriers. Free T4 were lower in patients with DICER1 polymorphisms (13.77 ± 1.8 vs. 15.44 ± 2.4 pmol/L, p = 0.008), regardless of TSH levels.

Conclusion

We conclude that germline DICER1 variants can be found in 11% of large goiters but no second-hit somatic mutation was found. DICER1 is one driver to thyroid lesion and a second-hit event seems unnecessary in the MNG development.

Landscape of somatic mutated genes and inherited susceptibility genes in gynecological cancer

Traditionally, gynecological cancers have been classified based on histology. Since remarkable advancements in next-generation sequencing technology have enabled the exploration of somatic mutations in various cancer types, comprehensive sequencing efforts have revealed the genomic landscapes of some common forms of human cancer. The genomic features of various gynecological malignancies have been reported by several studies of large-scale genomic cohorts, including The Cancer Genome Atlas. Although recent comprehensive genomic profiling tests, which can detect hundreds of genetic mutations at a time from cancer tissues or blood samples, have been increasingly used as diagnostic clinical biomarkers and in therapeutic management decisions, germline pathogenic variants associated with hereditary cancers can also be detected using this test. Gynecological cancers are closely related to genetic factors, with approximately 5% of endometrial cancer cases and 20% of ovarian cancer cases being caused by germline pathogenic variants. Hereditary breast and ovarian cancer syndrome and Lynch syndrome are the two major cancer susceptibility syndromes among gynecological cancers. In addition, several other hereditary syndromes have been reported to be associated with gynecological cancers. In this review, we highlight the genes for somatic mutation and germline pathogenic variants commonly seen in gynecological cancers. We first describe the relationship between clinicopathological attributes and somatic mutated genes. Subsequently, we discuss the characteristics and clinical management of inherited cancer syndromes resulting from pathogenic germline variants in gynecological malignancies.

[DICER1 syndrome: clinical variety endocrine manifestations and features of diagnostics]

DICER1 syndrome is a rare genetic disorder with the progressive development of malignant and non-malignant diseases in childhood. The cause of this syndrome is a dusfunction of the endoribonuclease DICER, which plays an important role in the processing of microRNAs with subsequent regulation of the control of the expression of oncogenes and tumor suppressor genes. Clinical manifestations of dyseropathies is very different and may include both endocrine manifestations - multinodular goiter, differentiated thyroid cancers, ovarian stromal tumors, pituitary blastoma, and non-endocrine formations - pleuropulmonary blastoma, cystic nephroma, pineoblastoma. The presence of somatic mutations of the DICER1 gene is a resultant stage in the pathogenesis of dyseropathies, determining the further path of oncogenesis. At present, DICER1 syndrome is diagnosed extremely rarely, which leads to late detection of the components of the disease in the patient, late diagnosis of neoplasms, lack of family counseling. Diagnosis at the early stages of the disease, the development of screening programs for the management of these patients allows minimizing the risks of developing more malignant, aggressive forms of the disease.

DICER1-associated central nervous system sarcoma: A comprehensive clinical and genomic characterization of case series of young adult patients

Background

DICER1 alterations are associated with intracranial tumors in the pediatric population, including pineoblastoma, pituitary blastoma, and the recently described "primary DICER1-associated CNS sarcoma" (DCS). DCS is an extremely aggressive tumor with a distinct methylation signature and a high frequency of co-occurring mutations. However, little is known about its treatment approach and the genomic changes occurring after exposure to chemoradiotherapy.

Methods

We collected clinical, histological, and molecular data from eight young adults with DCS. Genomic analysis was performed by Next-generation Sequencing (NGS). Subsequently, an additional germline variants analysis was completed. In addition, an NGS analysis on post-progression tumor tissue or liquid biopsy was performed when available. Multiple clinicopathological characteristics, treatment variables, and survival outcomes were assessed.

Results

Median age was 20 years. Most lesions were supratentorial. Histology was classified as fusiform cell sarcomas (50%), undifferentiated (unclassified) sarcoma (37.5%), and chondrosarcoma (12.5%). Germline pathogenic DICER1 variants were present in two patients, 75% of cases had more than one somatic alteration in DICER1, and the most frequent commutation was TP53. Seven patients were treated with surgery, Ifosfamide, Cisplatin, and Etoposide (ICE) chemotherapy and radiotherapy. The objective response was 75%, and the median time to progression (TTP) was 14.5 months. At progression, the most common mutations were in KRAS and NF1. Overall survival was 30.8 months.

Conclusions

DCS is an aggressive tumor with limited therapeutic options that requires a comprehensive diagnostic approach, including molecular characterization. Most cases had mutations in TP53, NF1, and PTEN, and most alterations at progression were related to MAPK, RAS and PI3K signaling pathways.

DICER1 Syndrome: A Multicenter Surgical Experience and Systematic Review

DICER1 syndrome is a rare genetic disorder that predisposes patients to the development of malignant and non-malignant diseases. Presently, DICER1 syndrome diagnosis still occurs late, usually following surgical operations, affecting patients' outcomes, especially for further neoplasms, which are entailed in this syndrome. For this reason, herein we present a multicenter report of DICER1 syndrome, with the prospective aim of enhancing post-surgical surveillance. A cohort of seven patients was collected among the surgical registries of Pediatric Surgery at the University of Pisa with the General and Oncologic Surgery of Federico II, University of Naples, and the Pediatric Surgery, Regina Margherita Hospital, University of Turin. In each case, the following data were analyzed: sex, age at diagnosis, age at first surgery, clinical features, familial, genetic investigations, and follow-up. A comprehensive literature review of DICER1 cases, including case reports and multicenter studies published from 1996 to June 2022, was performed. Eventually, the retrieved data from the literature were compared with the data emerging from our cohort of patients.

Comparative Biochemical Studies of Disease-Associated Human Dicer Mutations on Processing of a Pre-microRNA and snoRNA

Dicer is an RNase III enzyme that is responsible for the maturation of small RNAs such as microRNAs. As Dicer's cleavage products play key roles in promoting cellular homeostasis through the fine-tuning of gene expression, dysregulation of Dicer activity can lead to several human diseases, including cancers. Mutations in Dicer have been found to induce tumorigenesis and lead to the development of a rare pleiotropic tumor predisposition syndrome found in children and young adults called DICER1 syndrome. These patients harbor germline and somatic mutations in Dicer that lead to defective microRNA processing and activity. While most mutations occur within Dicer's catalytic RNase III domains, alterations within the Platform-PAZ (Piwi-Argonaute-Zwille) domain also cause loss of microRNA production. Using a combination of in vitro biochemical and cellular studies, we characterized the effect of disease-relevant Platform-PAZ-associated mutations on the processing of a well-studied oncogenic microRNA, pre-microRNA-21. We then compared these results to those of a representative from another Dicer substrate class, the small nucleolar RNA, snord37. From this analysis, we provide evidence that mutations within the Platform-PAZ domain result in differential impacts on RNA binding and processing, adding new insights into the complexities of Dicer processing of small RNA substrates.

Specifications of the ACMG/AMP Variant Classification Guidelines for Germline DICER1 Variant Curation

Germline pathogenic variants in DICER1 predispose individuals to develop a variety of benign and malignant tumors. Accurate variant curation and classification is essential for reliable diagnosis of DICER1-related tumor predisposition and identification of individuals who may benefit from surveillance. Since 2015, most labs have followed the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG/AMP) sequence variant classification guidelines for DICER1 germline variant curation. However, these general guidelines lack gene-specific nuances and leave room for subjectivity. Consequently, a group of DICER1 experts joined ClinGen to form the DICER1 and miRNA-Processing Genes Variant Curation Expert Panel (VCEP), to create DICER1- specific ACMG/AMP guidelines for germline variant curation. The VCEP followed the FDA-approved ClinGen protocol for adapting and piloting these guidelines. A diverse set of 40 DICER1 variants were selected for piloting, including 14 known Pathogenic/Likely Pathogenic (P/LP) variants, 12 known Benign/Likely Benign (B/LB) variants, and 14 variants classified as variants of uncertain significance (VUS) or with conflicting interpretations in ClinVar. Clinically meaningful classifications (i.e., P, LP, LB, or B) were achieved for 82.5% (33/40) of the pilot variants, with 100% concordance among the known P/LP and known B/LB variants. Half of the VUS or conflicting variants were resolved with four variants classified as LB and three as LP. These results demonstrate that the DICER1-specific guidelines for germline variant curation effectively classify known pathogenic and benign variants while reducing the frequency of uncertain classifications. Individuals and labs curating DICER1 variants should consider adopting this classification framework to encourage consistency and improve objectivity.

The Spectrum of Familial Pituitary Neuroendocrine Tumors

Hereditary pituitary tumorigenesis is seen in a relatively small proportion (around 5%) of patients with pituitary neuroendocrine tumors (PitNETs). The aim of the current review is to describe the main clinical and molecular features of such pituitary tumors associated with hereditary or familial characteristics, many of which have now been genetically identified. The genetic patterns of inheritance are classified into isolated familial PitNETs and the syndromic tumors. In general, the established genetic causes of familial tumorigenesis tend to present at a younger age, often pursue a more aggressive course, and are more frequently associated with growth hormone hypersecretion compared to sporadic tumors. The mostly studied molecular pathways implicated are the protein kinase A and phosphatidyl-inositol pathways, which are in the main related to mutations in the syndromes of familial isolated pituitary adenoma (FIPA), Carney complex syndrome, and X-linked acrogigantism. Another well-documented mechanism consists of the regulation of p27 or p21 proteins, with further acceleration of the pituitary cell cycle through the check points G1/S and M/G1, mostly documented in multiple endocrine neoplasia type 4. In conclusion, PitNETs may occur in relation to well-established familial germline mutations which may determine the clinical phenotype and the response to treatment, and may require family screening.

Next-generation sequencing of 500 POI patients identified novel responsible monogenic and oligogenic variants

BACKGROUND

Premature ovarian insufficiency refers to the loss of ovarian function before 40 years of age. The etiology is heterogeneous, and genetic factors account for 20-25% of cases. However, how to transform genetic findings to clinical molecular diagnose remains a challenge. To identify potential causative variations for POI, a next generation sequencing panel with 28 known causative genes of POI was designed, and a large cohort of 500 Chinese Han patients was screened directly. Pathogenic evaluation of the identified variants and the phenotype analysis were performed according to monogenic or oligogenic variants.

RESULTS

A total of 14.4% (72/500) of the patients carried 61 pathogenic or likely pathogenic variants in 19 of the genes in the panel. Interestingly, 58 variants (95.1%, 58/61) were firstly identified in patients with POI. FOXL2 harbored the highest occurrence frequency (3.2%, 16/500), among whom presented with isolated ovarian insufficiency instead of blepharophimosis-ptosis-epicanthus inversus syndrome. Moreover, luciferase reporter assay confirmed variant p.R349G, which account for 2.6% of POI cases, impaired the transcriptional repressive effect of FOXL2 on CYP17A1. The novel compound heterozygous variants in NOBOX and MSH4 were confirmed by pedigree haplotype analysis, and digenic heterozygous variants in MSH4 and MSH5 were firstly identified. Furthermore, nine patients (1.8%, 9/500) with digenic or multigenic pathogenic variants presented with delayed menarche, early onset of POI and high prevalence of primary amenorrhea compared with those with monogenic variation(s).

CONCLUSIONS

The genetic architecture of POI has been enriched through the targeted gene panel in a large cohort of patients with POI. Specific variants in pleiotropic genes may result in isolated POI rather than syndromic POI, whereas oligogenic defects might have cumulative deleterious effects on the severity of POI phenotype.

Structural Insights into the Advances and Mechanistic Understanding of Human Dicer

The RNase III endoribonuclease Dicer was discovered to be associated with cleavage of double-stranded RNA in 2001. Since then, many advances in our understanding of Dicer function have revealed that the enzyme plays a major role not only in microRNA biology but also in multiple RNA interference-related pathways. Yet, there is still much to be learned regarding Dicer structure-function in relation to how Dicer and Dicer-like enzymes initiate their cleavage reaction and release the desired RNA product. This Perspective describes the latest advances in Dicer structural studies, expands on what we have learned from this data, and outlines key gaps in knowledge that remain to be addressed. More specifically, we focus on human Dicer and highlight the intermediate processing steps where there is a lack of structural data to understand how the enzyme traverses from pre-cleavage to cleavage-competent states. Understanding these details is necessary to model Dicer's function as well as develop more specific microRNA-targeted therapeutics for the treatment of human diseases.

KMT2A‐D pathogenicity, prevalence, and variation according to a population database

INTRODUCTION

The KMT2 family of genes is essential epigenetic regulators promoting gene expression. The gene family contains three subgroups, each with two paralogues: KMT2A and KMT2B; KMT2C and KMT2D; KMT2F and KMT2G. KMT2A-D are among the most frequent somatically altered genes in several different cancer types. Somatic KMT2A rearrangements are well-characterized in infant leukemia (IL), and growing evidence supports the role of additional family members (KMT2B, KMT2C, and KMT2D) in leukemogenesis. Enrichment of rare heterozygous frameshift variants in KMT2A and C has been reported in acute myeloid leukemia (AML), IL, and solid tumors. Currently, the non-synonymous variation, prevalence, and penetrance of these four genes are unknown.

METHODS

This study determined the prevalence of pathogenic/likely pathogenic (P/LP) germline KMT2A-D variants in a cancer-free adult population from the Genome Aggregation Database (gnomAD). Two methods of variant interpretation were utilized: a manual genomic variant interpretation and an automated ACMG pipeline.

RESULTS

The ACMG pipeline identified considerably fewer P/LP variants (n = 89) compared to the manual method (n = 660) in all 4 genes. Consequently, the total P/LP prevalence and allele frequency (AF) were higher in the manual method (1:112, AF = 4.46E-03) than in ACMG (1:832, AF = 6.01E-04). Multiple ancestry-exclusive P/LP variants were identified along with an increased frequency in males compared to females. Many of these variants identified in this population database are also associated with severe juvenile conditions.

CONCLUSION

These data demonstrate that putatively functional germline variation in these developmentally important genes is more common than previously appreciated and identification in cancer-free adults may indicate incomplete penetrance for many of these variants. Future research should examine a genetic predisposing role in IL and other pediatric cancers.

Hereditary Gynecologic Cancer Syndromes - A Narrative Review

Hereditary cancer syndromes are defined as syndromes, where the genetics of cancer are the result of low penetrant polymorphisms or of a single gene disorder inherited in a mendelian fashion. During the last decade, compelling evidence has accumulated that approximately 5-10% of all cancers could be attributed to hereditary cancer syndromes. A tremendous progress has been made over the last decade in the evaluation and management of these syndromes. However, hereditary syndromes associated with gynecologic malignancies still present significant challenge for oncogynecologists. Oncogynecologists tend to pay more attention to staging, histological type and treatment options of gynecological cancers than thinking of inherited cancers and taking a detailed family history. Moreover, physicians should also be familiar with screening strategies in patients with inherited gynecological cancers. Lynch syndrome and hereditary breast-ovarian cancer syndrome are the most common and widely discussed syndromes in medical literature. The aim of the present review article is to delineate and emphasize the majority of hereditary gynecological cancer syndromes, even these, which are rarely reported in oncogynecology. The following inherited cancers are briefly discussed: Lynch syndrome; "site-specific" ovarian cancer and hereditary breast-ovarian cancer syndrome; Cowden syndrome; Li-Fraumeni syndrome; Peutz-Jeghers syndrome; ataxia-telangiectasia; DICER1- syndrome; gonadal dysgenesis; tuberous sclerosis; multiple endocrine neoplasia type I, II; hereditary small cell carcinoma of the ovary, hypercalcemic type and hereditary undifferentiated uterine sarcoma; hereditary diffuse gastric cancer and MUTYH-associated polyposis. Epidemiology, pathogenesis, diagnosis, pathology and screening of these syndromes are discussed. General treatment recommendations are beyond the scope of this review.

Mechanism underlying the effect of Liujunzi decoction on advanced-stage non-small cell lung cancer in patients after first-line chemotherapy

OBJECTIVE

To further clarify the anticancer mechanisms of Liujunzi decoction and provide possible targets for the treatment of advanced-stage nonsmall cell lung cancer (NSCLC) by re-analyzing differential gene expression profile of peripheral blood mononuclear cells (PBMCs) from Liujunzi decoctiontreated NSCLC patients receiving first-line chemotherapy.

METHODS

The PBMC gene expression microarray data set GSE61926 was retrieved from a high throughput gene expression database. Differentially expressed genes (DEGs) were screened by paired sample t-test and the multiple ratio method. Gene ontology and Kyoto encyclopedia of genes and genomes (KEGG) pathway analyses were performed using the DAVID database. The protein-protein interaction (PPI) network was constructed using interaction gene library retrieval tools and Cytoscape software.

RESULTS

A total of 162 DEGs were identified, with 67 upregulated genes and 95 downregulated genes. The functional distribution of Gene Oncology (GO) genes showed that DEGs were mostly concentrated in extracellular regions, calcium ion binding, and transcriptase activity. KEGG pathway analysis showed that cytokine-cytokine receptor interactions were significantly enriched. PPI network analysis screened out the top 10 central protein-coding genes with the highest nodal degree: IL2, PIWIL4, DICER1, PIWIL2, SAA1, XCL1, IL22RA1, ARHGAP11A, DCP1A, and GDNF. Among them, the central protein-coding gene with the highest node degree was IL2. In addition, the central protein-coding genes with high node degrees and high molecular complex detection (MCODE) scores were PIWIL4, DICER1, PIWIL2, and DCP1A, all of which are related to tumor development.

CONCLUSIONS

One signaling pathway and 10 central protein-coding genes related to anticancer mechanisms were screened by re-analysis of GSE61926 data. IL2, PIWIL4, DICER1, PIWIL2, and DCP1A may have important roles in the mechanism of Liujunzi decoction treatment against NSCLC. Our results suggest that the anticancer mechanism of Liujunzi decoction may be related to gene silencing by RNA and the biological processes of piwi-interacting RNA and other small RNAs.

Multimodality Imaging of Pleuropulmonary Blastoma: Pearls, Pitfalls, and Differential Diagnosis

Pleuropulmonary blastomas are rare, potentially aggressive embryonal cancers of the lung parenchyma and pleural surfaces that account for 0.25%-0.5% of primary pulmonary malignancies in children. Pleuropulmonary blastomas are classified as cystic (type I), mixed cystic and solid (type II), and solid (type III). Pleuropulmonary blastoma occurs in the same age group (0-6 years) as other more common solid tumors such as neuroblastoma and Wilms tumor. Differential diagnosis includes metastasis from Wilms tumor and macrocystic congenital pulmonary airway malformation (CPAM). A key pathologic and genetic discriminator is the DICER1 germline mutation found in patients with pleuropulmonary blastoma. Imaging, histopathologic, and clinical data are important to use in conjunction in order to determine the diagnosis and risk stratification of pleuropulmonary blastomas. Survival varies from poor to good, depending on type. However, the spectrum of pleuropulmonary blastoma is insufficiently understood due to the variable presentation of this rare disease. We present a current review of the literature regarding pleuropulmonary blastomas in this article.

Expanding the spectrum of thyroid carcinoma with somatic DICER1 mutation: a survey of 829 thyroid carcinomas using MSK-IMPACT next-generation sequencing platform

DICER1 gene encodes an RNaseIII endoribonuclease essential for the cleavage of pre-microRNA to mature microRNA. Germline DICER1 mutation results in DICER syndrome, a cancer predisposition syndrome which manifests in the thyroid gland as early-onset multinodular goiter and increased risk for differentiated thyroid carcinoma. Recently, somatic DICER1 mutations were described in various thyroid neoplasms, including follicular adenoma, papillary thyroid carcinoma, follicular carcinoma, and poorly differentiated thyroid carcinoma. In this study, we identified and described 14 cases (1.7%) with somatic DICER1 mutations from a cohort of 829 patients with thyroid follicular cell-derived thyroid carcinomas which were sequenced using MSK-IMPACT targeted next-generation sequencing platform. We expanded the histologic spectrum of thyroid carcinomas with somatic DICER1 mutations to include Hurthle cell carcinoma, high-grade differentiated thyroid carcinoma, and anaplastic thyroid carcinoma. All patients were adults with a median age of diagnosis of 59 years (range: 22-82). Although rare, a subset of thyroid cancers, including the aggressive subtypes, display somatic DICER1 mutations, some of which have oncogenic potential.

Rare Hereditary Gynecological Cancer Syndromes

Hereditary cancer syndromes, which are characterized by onset at an early age and an increased risk of developing certain tumors, are caused by germline pathogenic variants in tumor suppressor genes and are mostly inherited in an autosomal dominant manner. Therefore, hereditary cancer syndromes have been used as powerful models to identify and characterize susceptibility genes associated with cancer. Furthermore, clarification of the association between genotypes and phenotypes in one disease has provided insights into the etiology of other seemingly different diseases. Molecular genetic discoveries from the study of hereditary cancer syndrome have not only changed the methods of diagnosis and management, but have also shed light on the molecular regulatory pathways that are important in the development and treatment of sporadic tumors. The main cancer susceptibility syndromes that involve gynecologic cancers include hereditary breast and ovarian cancer syndrome as well as Lynch syndrome. However, in addition to these two hereditary cancer syndromes, there are several other hereditary syndromes associated with gynecologic cancers. In the present review, we provide an overview of the clinical features, and discuss the molecular genetics, of four rare hereditary gynecological cancer syndromes; Cowden syndrome, Peutz-Jeghers syndrome, DICER1 syndrome and rhabdoid tumor predisposition syndrome 2.

The Multifaceted Profile of Thyroid Disease in the Background of DICER1 Germline and Somatic Mutations: Then, Now and Future Perspectives

DICER1 protein is a member of the ribonuclease (RNAse) III family with a key role in the biogenesis of microRNAs (miRNA) and in microRNA processing, potentially affecting gene regulation at the post-transcriptional level. The role of DICER1 and its relevance to thyroid cellular processes and tumorigenesis have only recently been explored, following the acknowledgement that DICER1 germline and somatic changes can contribute not only to non-toxic multinodule goiter (MNG) lesions detected in individuals of affected families but also to a series of childhood tumours, including thyroid neoplasms, which can be identified from early infancy up until the decade of 40s. In a context of DICER1 germline gene mutation, thyroid lesions have recently been given importance, and they may represent either an index event within a syndromic context or the isolated event that may trigger a deeper and broader genomic analysis screening of individuals and their relatives, thereby preventing the consequences of a late diagnosis of malignancy. Within the syndromic context MNG is typically the most observed lesion. On the other hand, in a DICER1 somatic mutation context, malignant tumours are more common. In this review we describe the role of DICER protein, the genomic events that affect the DICER1 gene and their link to tumorigenesis as well as the frequency and pattern of benign and malignant thyroid lesions and the regulation of DICER1 within the thyroidal environment.

DICER1 tumor predisposition syndrome: an evolving story initiated with the pleuropulmonary blastoma

DICER1 syndrome (OMIM 606241, 601200) is a rare autosomal dominant familial tumor predisposition disorder with a heterozygous DICER1 germline mutation. The most common tumor seen clinically is the pleuropulmonary blastoma (PPB), a lung neoplasm of early childhood which is classified on its morphologic features into four types (IR, I, II and III) with tumor progression over time within the first 4-5 years of life from the prognostically favorable cystic type I to the unfavorable solid type III. Following the initial report of PPB, its association with other cystic neoplasms was demonstrated in family studies. The detection of the germline mutation in DICER1 provided the opportunity to identify and continue to recognize a number seemingly unrelated extrapulmonary neoplasms: Sertoli-Leydig cell tumor, gynandroblastoma, embryonal rhabdomyosarcomas of the cervix and other sites, multinodular goiter, differentiated and poorly differentiated thyroid carcinoma, cervical-thyroid teratoma, cystic nephroma-anaplastic sarcoma of kidney, nasal chondromesenchymal hamartoma, intestinal juvenile-like hamartomatous polyp, ciliary body medulloepithelioma, pituitary blastoma, pineoblastoma, primary central nervous system sarcoma, embryonal tumor with multilayered rosettes-like cerebellar tumor, PPB-like peritoneal sarcoma, DICER1-associated presacral malignant teratoid neoplasm and other non-neoplastic associations. Each of these neoplasms is characterized by a second somatic mutation in DICER1. In this review, we have summarized the salient clinicopathologic aspects of these tumors whose histopathologic features have several overlapping morphologic attributes particularly the primitive mesenchyme often with rhabdomyoblastic and chondroid differentiation and an uncommitted spindle cell pattern. Several of these tumors have an initial cystic stage from which there is progression to a high grade, complex patterned neoplasm. These pathologic findings in the appropriate clinical setting should serve to alert the pathologist to the possibility of a DICER1-associated neoplasm and initiate appropriate testing on the neoplasm and to alert the clinician about the concern for a DICER1 mutation.

Surveillance recommendations for DICER1 pathogenic variant carriers: a report from the SIOPE Host Genome Working Group and CanGene-CanVar Clinical Guideline Working Group

DICER1 syndrome is a rare genetic disorder that predisposes to a wide spectrum of tumors. Developing surveillance protocols for this syndrome is challenging because uncertainty exists about the clinical efficacy of surveillance, and appraisal of potential benefits and harms vary. In addition, there is increasing evidence that germline DICER1 pathogenic variants are associated with lower penetrance for cancer than previously assumed. To address these issues and to harmonize DICER1 syndrome surveillance programs within Europe, the Host Genome Working Group of the European branch of the International Society of Pediatric Oncology (SIOPE HGWG) and Clinical Guideline Working Group of the CanGene-CanVar project in the United Kingdom reviewed current surveillance strategies and evaluated additional relevant literature. Consensus was achieved for a new surveillance protocol and information leaflet that informs patients about potential symptoms of DICER1-associated tumors. The surveillance protocol comprises a minimum program and an extended version for consideration. The key recommendations of the minimum program are: annual clinical examination from birth to age 20 years, six-monthly chest X-ray and renal ultrasound from birth to age 6 years, and thyroid ultrasound every 3 years from age 8 to age 40 years. The surveillance program for consideration comprises additional surveillance procedures, and recommendations for DICER1 pathogenic variant carriers outside the ages of the surveillance interval. Patients have to be supported in choosing the surveillance program that best meets their needs. Prospective evaluation of the efficacy and patient perspectives of proposed surveillance recommendations is required to expand the evidence base for DICER1 surveillance protocols.

miR-340 Restrains the Growth of Lung Cancer Cells Through Mitogen-Activated Protein Kinase (MAPK) Signaling

The lung cancer was most deadly tumor in the world and the suvival rate needs to be improved clinically and urgently. The abnormal miR-340 expression is found in several solid tumors. Our study was aimed to explore miR-340’s role in lung cancer. 14 cases of patients with lung cancer was selected to measure miR-340 level by RT-PCR and analyze its correlation with clinical characteristics. The relation between the miR-340 and DICER1 was detected by dual luciferase assay and cell proliferation was measured by MTT assay along with analysis of cell migration and invasive by Scratch-Wound experiment. The miR-340 in lung cancer cells was reduced significantly and DICER1 was predicted to be a potential target of miR-340. DICER1 level was found to be negatively related with miR-340 level. The DICER1 as the direct target gene of miR-340 was conducive to improve miR-340 function through overexpression and knock-out experiment further. Abnormal miR-340 level affected lung cancer cell proliferation and migration as well as MAPK signaling. miR-340 could affect the biological morphology and transformation of physiological function of lung cancer cells mainly through restraining the expression of apoptosis and prompting the cellular proliferation, indicating that it might be a novel target to improve the treatment of lung cancer.

Spectrum of DICER1 Germline Pathogenic Variants in Ovarian Sertoli-Leydig Cell Tumor

Sertoli–Leydig Cell Tumors (SLCTs) are rare ovarian sex cord-stromal neoplasms, which predominantly affect adolescents and young female adults. The SLCTs clinical diagnosis and treatment remains challenging due to the rarity and the varied presentation. A large majority of SLCTs are unilateral, but also bilateral neoplasms have been reported, sometimes in the context of DICER1 syndrome. In fact, the most significant discovery regarding the molecular genetics basis of SLCTs was the finding of somatic and germline pathogenic variants in the DICER1 gene. The DICER1 protein is a key component of the micro-RNA processing pathway. Germline DICER1 pathogenic variants are typically inherited in an autosomal dominant pattern and are most often loss-of-function variants dispersed along the length of the gene. Contrarily, DICER1-related tumors harbor a characteristic missense “RNase IIIb hotspot” mutation occurring in trans, or, less frequently, loss of heterozygosity (LOH) event involving the wild-type allele. While DICER1 mutations have been identified in approximately 60% of SLCTs, especially in the moderately or poorly differentiated types, there are only a few case reports of ovarian SLCT with underlying germline DICER1 mutations. In this review, we focus on the molecular genetic features of SLCT, performing an extensive survey of all germline pathogenic variants modifying the whole sequence of the DICER1 gene. We point out that DICER1 genetic testing, coupled with an accurate variants classification and timely counseling, is of crucial importance in the clinical management of ovarian SLCT-affected patients.

The role of FOXL2, SOX9, and β-catenin expression and DICER1 mutation in differentiating sex cord tumor with annular tubules from other sex cord tumors of the ovary

Sex cord tumor with annular tubules (SCTAT) is a highly rare type of ovarian sex cord-stromal tumor (SCST), the diagnosis of which remains to be challenging. The aim of this study was to scrutinize the utility of three immunohistochemical markers including Forkhead box protein 2 (FOXL2), SOX9, and β-catenin and DICER1 mutation status in distinguishing SCTATs from other ovarian SCSTs. Nine cases of SCTAT, 10 Sertoli-Leydig cell tumor (SCLT), 10 adult-type granulosa cell tumor (AGCT), and 8 juvenile-type granulosa cell tumor (JGCT) were included in the study. SCTATs were characterized by diffuse and strong expression of SOX9, focal and weak expression of FOXL2, and the absence of DICER1 mutation. However, AGCTs and JGCTs displayed strong and diffuse expression of FOXL2, focal/no immunoreaction for SOX9. SLCTs generally showed moderate intensity of FOXL2 and SOX9 expression. Nuclear β-catenin expression was observed in none of SLCT, 1/9 of SCTAT, 6/8 JGCT, and 4/10 AGCT cases, respectively. DICER1 hotspot mutation was detected in only 3 cases of SLCT and 2 cases of JGCT. We conclude that in addition to strong and diffuse SOX9 expression, weak/absent expression of FOXL2 is suggestive for the diagnosis of SCTAT. Hence, we suggest that inclusion of these two markers, SOX-9 and FOXL2, to the immunohistochemical panel helps in differentiation of SCTAT from other SCSTs in addition to morphologic findings. We also conclude that SCTATs of the ovary do not harbor DICER1 hotspot mutation.

A Genome-First Approach to Characterize DICER1 Pathogenic Variant Prevalence, Penetrance, and Phenotype

IMPORTANCE

Genetic disorders are historically defined through phenotype-first approaches. However, risk estimates derived from phenotype-linked ascertainment may overestimate severity and penetrance. Pathogenic variants in DICER1 are associated with increased risks of rare and common neoplasms and thyroid disease in adults and children. This study explored how effectively a genome-first approach could characterize the clinical traits associated with germline DICER1 putative loss-of-function (pLOF) variants in an unselected clinical cohort.

OBJECTIVE

To examine the prevalence, penetrance, and phenotypic characteristics of carriers of germline DICER1 pLOF variants via genome-first ascertainment.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study classifies DICER1 variants in germline exome sequence data from 92 296 participants of the Geisinger MyCode Community Health Initiative. Data for each MyCode participant were used from the start of the Geisinger electronic health record to February 1, 2018.

MAIN OUTCOMES AND MEASURES

Prevalence of germline DICER1 variation; penetrance of malignant tumors and thyroid disease in carriers of germline DICER1 variation; structured, manual review of electronic health records; and DICER1 sequencing of available tumors from an associated cancer registry.

RESULTS

A total of 92 296 adults (mean [SD] age, 59 [18] years; 98% white; 60% female) participated in the study. Germline DICER1 pLOF variants were observed in 1 in 3700 to 1 in 4600 participants, more than double the expected prevalence. Malignant tumors (primarily thyroid carcinoma) were observed in 4 of 25 participants (16%) with DICER1 pLOF variants, which is comparable (by 50 years of age) to the frequency of neoplasms in the largest registry- and clinic-based (phenotype-first) DICER1 studies published to date. DICER1 pLOF variants were significantly associated with risks of thyroidectomy (odds ratio [OR], 6.0; 95% CI, 2.2-16.3; P = .007) and thyroid cancer (OR, 9.2; 95% CI, 2.1-34.7; P = .02) compared with controls, but there was not a significant increase in the risk of goiter (OR, 1.8; 95% CI, 0.7-4.9). A female patient in her 80s who was a carrier of a germline DICER1 hotspot variant was apparently healthy on electronic health record review. The term DICER1 did not appear in any of the medical records of the 25 participants with a pLOF DICER1 variant, even in those affected with a known DICER1-associated tumor or thyroid phenotype.

CONCLUSIONS AND RELEVANCE

This cohort study was able to ascertain individuals with germline DICER1 variants based on a genome-first approach rather than through a previously established DICER1-related phenotype. Use of the genome-first approach may complement more traditional approaches to syndrome delineation and may be an efficient approach for risk estimation.

Analyzing the Role of DICER1 Germline Variations in Papillary Thyroid Carcinoma

INTRODUCTION

DICER1 is a member of RNase III family that has a pivotal role in the biogenesis of microRNAs, being important for normal development. Dysregulation of DICER1 has been described in different human tumours; however, there is insufficient data on the risk of thyroid cancer in the presence of germline DICER1 variants, particularly when focusing on the background of papillary thyroid carcinoma (PTC). For this purpose, we ascertained the presence of DICER1 variants in 502 (PTC) cases available from The Cancer Genome Atlas (TCGA) research network in a well-characterized pathological context.

MATERIAL AND METHODS

in this study we analyzed 502 samples from 502 patients, described as PTC in the TCGA database. Tumour diagnoses were re-evaluated by 2 pathologists (S.C. and M.S.-S.) on slides available from the database, and clinicopathological and demographic data was examined. Data concerning germline and sporadic DICER1 gene variants as well as frequent mutations in the genes involved in thyroid carcinogenesis (e.g., RAS and BRAFV600E) was retrieved from the database.

RESULTS AND DISCUSSION

We report 1 new germline possibly pathogenic variant, besides 15 others already been identified in ClinVar. We found that the DICER1-positive PTC group more frequently includes PTC variants, namely the oncocytic, follicular, and aggressive (hobnail variant of PTC) variants. A previous association of DICER1 had been demonstrated, mainly with the follicular variant of PTC and follicular thyroid carcinomas. Tumours harbouring germline DICER1 mutations were more frequently "bilateral" and "encapsulated." The frequent association of DICER1 germline variants with other mutations associated with thyroid cancer can reflect an haploinsufficiency tumour suppressor gene function of DICER1, as suggested from the study of animal models.

Prevalence of Pathogenic Germline DICER1 Variants in Young Individuals Thyroidectomised Due to Goitre - A National Danish Cohort

INTRODUCTION

DICER1 syndrome encompasses a variety of benign and malignant manifestations including multinodular goitre, which is the most common manifestation among individuals carrying pathogenic DICER1 variants. This is the first study estimating the prevalence of pathogenic DICER1 variants in young individuals with multinodular goitre.

METHODS

Danish individuals diagnosed with nodular goitre based on thyroidectomy samples in 2001-2016 with the age limit at time of operation being ≤ 25 years were offered germline DICER1 gene testing.

RESULTS

Six of 46 individuals, 13% (CI [3.3;22.7], p <0.05), diagnosed with nodular goitre on the basis of thyroidectomy samples under the age of 25 years had pathogenic germline variants in DICER1. They were found in different pathoanatomical nodular goitre cohorts i.e. nodular goitre (n=2), colloid nodular goitre (n=3) and hyperplastic nodular goitre (n=1).

CONCLUSIONS

We recommend referral of patients thyroidectomised due to goitre aged <21 years and patients thyroidectomised due to goitre aged <25 years with a family history of goitre to genetic counselling. Patients of all ages thyroidectomised due to goitre, who are affected by another DICER1 manifestation should be referred to genetic counselling.

Somatic DICER1 Mutations in a Pubertal Girl with Cervical Embryonal Rhabdomyosarcoma and Papillary Thyroid Adenoma

BACKGROUND

DICER1 syndrome is an inherited tumor predisposition syndrome. A germline mutation in DICER1 increases the risk for a spectrum of rare tumors. We describe a case of somatic DICER1 mutation in a pubertal girl, who is affected by different tumors of the DICER1 syndrome, including embryonal rhabdomyosarcoma (ERMS) of the cervix and thyroid adenoma.

CASE

A 16-year-old girl with history of papillary thyroid adenoma presented with abnormal vaginal bleeding and an exophytic cervical mass on examination. Histopathologic examination confirmed cervical ERMS. By using Sanger sequencing of the tumor, we identified 1 DICER1 mutation (c.3937delG).

SUMMARY AND CONCLUSION

This report suggests that a patient with these 2 unrelated tumors (ERMS and papillary thyroid adenoma) should be promptly tested for DICER1 gene mutations.

Lack of pathogenic germline DICER1 variants in males with testicular germ-cell tumors

BACKGROUND

Several studies have reported conflicting evidence on the inclusion of testicular germ cell tumors (TGCT) in the DICER1 tumor-predisposition phenotype. We evaluated the relationship between DICER1 and TGCT by reviewing scrotal ultrasounds of males with pathogenic germline variants in DICER1 and queried exome data from TGCT-affected men for DICER1 variants.

METHODOLOGY

Fifty-four male DICER1-carriers and family controls (n=41) enrolled in the National Cancer Institute (NCI) DICER1 Natural History Study were offered scrotal ultrasounds. These studies were examined by a single radiologist for abnormalities. In parallel, DICER1 variants from two large exome-sequenced TGCT cohorts were extracted. We used previously published AMG-AMP criteria to characterize rare DICER1 variants.

RESULTS

There was no observed difference in frequency of testicular cystic structures in DICER1-carriers versus controls. DICER1 variation was not associated with TGCT in the NCI DICER1-carriers. In 1,264 exome-sequenced men with TGCT, none harbored ClinVar- or InterVar-determined pathogenic or likely pathogenic variants in DICER1. Three DICER1 variants of uncertain significance (one case and two controls) were predicted "damaging" based on a priori criteria.

CONCLUSION

Using two complementary approaches, we found no evidence of an association between pathogenic DICER1 variants and TGCT.

Germline predisposition to genitourinary rhabdomyosarcoma

Multiple genetic conditions predispose to the development of rhabdomyosarcoma. Much of the literature on rhabdomyosarcoma in genetic syndromes does not sub-divide the location or the pathology of the sarcomas. Therefore, there are limited data on genitourinary specific associations with certain genetic syndromes. We summarize, here, the primary differential considerations for rhabdomyosarcoma of the genitourinary system. Primary considerations include DICER1 pathogenic variation, Li-Fraumeni syndrome, constitutional mismatch repair deficiency, mosaic variegated aneuploidy, neurofibromatosis type 1, Noonan syndrome, other RASopathies, Costello syndrome, and Beckwith-Wiedemann syndrome. Some conditions may present with specific pathological, clinical and/or family history features, but for others, the genitourinary tumor may be the only presenting sign at the time of diagnosis. Genetic evaluation with counseling and/or testing may help identify an underlying tumor predisposition. This manuscript serves as an introduction to germline considerations for children with genitourinary rhabdomyosarcoma.

Clinical Characteristics and Mutation Analyses of Ovarian Sertoli-Leydig Cell Tumors

BACKGROUND

There are limited studies on Sertoli-Leydig cell tumors (SLCTs) and no data in the population of Chinese patients with SLCTs from the genetic level. In addition, previous studies on SLCTs have focused exclusively on mutations in the DICER1 gene and no data exists on the genetic landscape of SLCTs.

METHODS

Patients with moderately or poorly differentiated SLCTs who underwent surgical resection between January 2012 and October 2018 in our institution were recruited. Whole exome sequencing was performed on formalin-fixed, paraffin-embedded tumor tissue and peripheral blood or normal tissue samples.

RESULTS

Seventeen patients were recruited with 19 tumor samples. The rate of tumor-associated germline mutations was 6 of 17 (35.3%), and that of DICER1 germline mutations was 4 of 17 (23.5%). Regarding clinical relapse, patients with germline tumor-associated mutations had significantly poorer prognosis than those without (p = .007), and those with germline DICER1 mutations were relatively more likely to exhibit clinical relapse, although not to a significant degree (p = .069). Regarding somatic mutations, firstly, the subclone evolution analysis demonstrated that the two tumors on the contralateral ovary were primary tumors, respectively. Secondly, somatic mutations were most commonly found in CDC27 (10/19, 52.6%), DICER1 (4/19, 21.1%), and MUC22 (4/19, 21.1%). And the analysis of cancer cell fractions showed that DICER1 mutations were correlated with tumorigenesis of SLCTs. The rates of germline and somatic DICER1 mutations were higher in patients who were younger than 18 years than those in older patients (p = .022 and p = .001, respectively).

CONCLUSION

Our study indicates that genetic testing may have important clinical significance for patients with SLCTs, particularly for younger patients.

IMPLICATIONS FOR PRACTICE

Bilateral ovarian Sertoli-Leydig cell tumors were verified to be primary tumors from the genetic perspective. The rates of germline and somatic DICER1 mutations were 4 of 17 (23.5%) and 4 of 19 (21.1%), respectively. The rates of germline and somatic DICER1 mutations were higher in patients who were younger than 18 years than those in older patients (p = .022 and p = .001, respectively).

DICER1 Hotspot Mutations in Pleuropulmonary Blastoma: A Case Series From a Tertiary Center

Pleuropulmonary blastoma (PPB) is a potentially aggressive, rare childhood neoplasia. We investigated histopathological features, survival, and DICER1 hotspot mutations among PPB patients. Archive records at our institution were reviewed, covering a 20-year period. Thirteen children (6 males and 7 females) with a mean age of 30.5 (range 6-83) months were included. The tumor subtypes were type I in 6 (46%), type II in 4 (31%), and type III in 3 (23%). Only tumors with type II and type III histology showed anaplasia (4/7, 57%). Median follow-up was 28 (range 9-216) months. Three-year overall survival rate was 83.3% and 3-year progression-free survival rate was 25%. Progression was seen in 60% (3/5) of type I and 66.7% (4/6) of type II and type III cases. Two patients died of disseminated disease at 9 and 44 months. Hotspot missense mutations on DICER1 gene were detected in all 11 patients with available tumor tissue. We found an additional novel germline loss-of-function mutation (c.5436dupT; p.E1813*) in 1 case. To the best of our knowledge, this is the first study to investigate hotspot missense mutations on DICER1 gene among the largest series of Turkish children with PPB.

Secondary Sarcomas: Biology, Presentation, and Clinical Care

Secondary sarcomas are a subset of sarcomas that occur in patients with prior cancer diagnoses and are associated with environmental or genetic factors. Although secondary sarcomas are rare in general, there are predisposing factors that can substantially increase this risk in certain populations. Herein, we review the environmental factors with the strongest association of sarcoma risk, including chemical exposure, certain viruses, cytotoxic and immunosuppressive agents, chronic edema, and radiation exposure. Additionally, the most common genetic disorders that carry a predisposition for sarcoma development will be discussed, including hereditary retinoblastoma (RB), Li-Fraumeni syndrome (LFS), neurofibromatosis type 1 (NF1), and DICER1 syndrome. Although treatment does not generally differ for sporadic versus secondary sarcomas, awareness of the risk factors can alter therapeutic strategies to minimize risk, aid prompt diagnosis by increasing clinical suspicion, and allow for appropriate surveillance and genetic counseling for those patients with cancer predisposition syndromes.

Challenges and solutions to the study of rare childhood tumors

PURPOSE OF REVIEW

The majority of progress made in pediatric oncology over the past 50 years has been achieved in the most common cancers. Rare pediatric cancers, which collectively comprise more than 10% of all pediatric cancers, pose multiple challenges to researchers and clinicians, all which stem from the infrequency of these cancers. There has been a tremendous increase in focus on rare pediatric cancers by international consortia and registries, disease-specific clinics, and divisions of academic children's hospitals in the last 10 years. This focus, along with the progress made in cancer genomics, has changed the landscape for the study and treatment of rare pediatric cancers. This review focuses on the past, present, and future of the study and treatment of rare pediatric cancers.

RECENT FINDINGS

Cancer genomics is changing the way some cancers are being diagnosed, categorized, and treated. Rare pediatric cancers potentially stand to greatly benefit from advances in precision diagnosis and treatment.

SUMMARY

The challenges of studying rare pediatric cancers are well known. By utilizing similar techniques that allowed for progress in the common pediatric malignancies, namely collaboration, increased focus, greater funding, and utilization of cancer genomics, progress in the study and treatment of rare pediatric cancers is promising.

Rare Germline DICER1 Variants in Pediatric Patients With Cushing's Disease: What Is Their Role?

Context: The DICER1 syndrome is a multiple neoplasia disorder caused by germline mutations in the DICER1 gene. In DICER1 patients, aggressive congenital pituitary tumors lead to neonatal Cushing's disease (CD). The role of DICER1 in other corticotropinomas, however, remains unknown. Objective: To perform a comprehensive screening for DICER1 variants in a large cohort of CD patients, and to analyze their possible contribution to the phenotype. Design, setting, patients, and interventions: We included 192 CD cases: ten young-onset (age <30 years at diagnosis) patients were studied using a next generation sequencing panel, and 182 patients (170 pediatric and 12 adults) were screened via whole-exome sequencing. In seven cases, tumor samples were analyzed by Sanger sequencing. Results: Rare germline DICER1 variants were found in seven pediatric patients with no other known disease-associated germline defects or somatic DICER1 second hits. By immunohistochemistry, DICER1 showed nuclear localization in 5/6 patients. Variant transmission from one of the parents was confirmed in 5/7 cases. One patient had a multinodular goiter; another had a family history of melanoma; no other patients had a history of neoplasms. Conclusions: Our findings suggest that DICER1 gene variants may contribute to the pathogenesis of non-syndromic corticotropinomas. Clarifying whether DICER1 loss-of-function is disease-causative or a mere disease-modifier in this setting, requires further studies. Clinical trial registration: ClinicalTrials.gov: NCT00001595.

Multinodular goitre is a gateway for molecular testing of DICER1 syndrome

BACKGROUND

DICER1 syndrome is an autosomal dominant disorder that predisposes individuals to develop benign or malignant tumours from infancy to adulthood. There is low-to-moderate penetrance of tumour development, which is sex- and age-dependent. Multinodular goitre (MNG) is among the most highly penetrant phenotype of the disorder, especially in females.

PATIENTS AND METHODS

We report a series of eight families referred for childhood-onset of MNG or DICER1-related tumours with familial history of MNG in relatives. No additional families with these criteria stated were identified during the same date. We screened DNA samples from the probands and members of their family (40) for constitutional DICER1 variants using Next Generation Sequencing tools.

RESULTS

Germline pathogenic DICER1 gene variants were identified in all probands and several of their relatives: 64% presented with MNG/thyroidectomy as the phenotypic expression of the syndrome. DICER1 gene variants were identified in the RNAseIII and the PAZ domains. All tumour tissues studied presented clonal pathogenic variants in hotspot regions. Early identification of DICER1 variant carriers has permitted diagnosis and therapeutic scheme correction for two patients and cascade testing in relatives.

CONCLUSIONS

Multinodular goitre is uncommon in children. Childhood-onset MNG, multiple occurrences of the disease within the same family, or its association with rare benign or malignant tumours should raise suspicions of anomalies in the DICER1 gene, as proposed by recent international recommendations. Early detection of DICER1 pathogenic variants has important consequences in terms of therapeutic strategy, early tumour screening, and genetic counselling.

Use of Big Data to Estimate Prevalence of Defective DNA Repair Variants in the US Population

Importance

Wide use of genomic sequencing to diagnose disease has raised concern about the extent of genotype-phenotype correlations.

Objective

To correlate disease-associated allele frequencies with expected and reported prevalence of clinical disease.

Design, Setting, and Participants

Xeroderma pigmentosum (XP), a recessive, cancer-prone, neurocutaneous disorder, was used as a model for this study. From January 1, 2017, to May 4, 2018, the Human Gene Mutation Database and a cohort of patients at the National Institutes of Health were searched and screened to identify reported mutations associated with XP. The clinical phenotype of these patients was confirmed from reports in the literature and National Institutes of Health medical records. The genetically predicted prevalence of disease based on frequency of known pathogenic mutations was compared with the prevalence of patients clinically diagnosed with phenotypic XP. Exome sequencing of more than 200 000 alleles from the Genome Aggregation Database, the National Cancer Institute Division of Cancer Epidemiology and Genetics database of healthy controls, and an Inova Hospital Study database was used to investigate the frequencies of these mutations in the general population.

Main Outcomes and Measures

Listing of all reported mutations associated with XP, their frequencies in 3 large exome sequence databases, determination of the number of patients in the United States with XP using modeling equations, and comparison of the observed and reported numbers of patients with XP with specific mutations.

Results

A total of 156 pathogenic missense and nonsense mutations associated with XP were identified in the National Institutes of Health cohort and the Human Gene Mutation Database. The Genome Aggregation Database provided frequency data for 65 of these mutations, with a total allele frequency of 1.13%. The XPF (ERCC4) mutation, p.P379S, had an allele frequency of 0.4%, and the XPC mutation, p.P334H, had an allele frequency of 0.3%. With the Hardy-Weinberg equation, it was determined that there should be more than 8000 patients who are homozygous for these mutations in the United States. In contrast, only 3 patients with XP were reported as having the XPF mutation, and 1 patient was reported as having the XPC mutation.

Conclusions and Relevance

The findings from this study suggest that clinicians should approach large genomic databases with caution when trying to correlate the clinical implications of genetic variants with the prevalence of disease risk. Unsuspected mutations in known genes with a predisposition for skin cancer may be responsible for some of the high frequency of skin cancers in the general population.

Imaging of DICER1 syndrome

DICER1 syndrome is a highly pleiotropic tumor predisposition syndrome that has been increasingly recognized in the last 10 years. Diseases in the syndrome result from mutations in both copies of the gene DICER1, a highly conserved gene that is critically implicated in micro-ribonucleic acid (miRNA) biogenesis and hence modulation of messenger RNAs. In general, susceptible individuals carry an inherited germline mutation that disables one copy of DICER1; within tumors, a very characteristic second mutation alters function of the other gene copy. About 20 hamartomatous, hyperplastic or neoplastic conditions comprise DICER1 syndrome. Most are not life-threatening, but some are aggressive malignancies. There are many unaffected carriers because penetrance is generally low; however, clinically occult thyroid nodules and lung cysts are frequent. Rare diseases of early childhood were the first recognized conditions in DICER1 syndrome, while other conditions affect adolescents and adults. The hallmarks of DICER1 syndrome are certain rare tumors including pleuropulmonary blastoma; cystic nephroma; ovarian Sertoli-Leydig cell tumor; sarcomas of the cervix, kidneys and cerebrum; pituitary blastoma; ciliary body medulloepithelioma; and nasal chondromesenchymal hamartoma. Radiologists are often the first practitioners to observe these diverse manifestations and play a primary role in recognizing DICER1 syndrome.

Dental abnormalities in individuals with pathogenic germline variation in DICER1

Pathogenic germline variation in the microRNA processing gene DICER1 gives rise to an autosomal dominant, tumor-predisposition disorder. Conditional deletion of Dicer1 in murine dental epithelium shows that it controls tooth patterning, size, number, and shape. The human dental phenotype of people with germline pathogenic variation in DICER1 is unknown. DICER1-carriers (n = 57) and family controls (n = 55) were evaluated at the NIH Clinical Center dental clinic as part of a comprehensive medical evaluation. Digital panoramic radiographs, bite-wing radiographs, and oral photographs were collected. A single observer, blind to DICER1 status, reviewed the dental records and determined the presence or absence of 11 dental characteristics as described in the clinic notes, radiographs, or oral photographs. Subjective phenotypes were reviewed on radiographs by two examiners (blind to DICER1 status) for the presence or absence of the dental characteristics to reduce inconsistencies. By simple association, bulbous crown, periodontitis, and taurodontism were all significant (p < .05). Logistic regression with chi-square maximum likelihood estimates showed that bulbous crown and periodontitis remained significant. Recognition of these phenotypes may aid identification of individuals and families at risk for DICER1-associated neoplasms. These findings may also guide dental care for individuals with germline DICER1 pathogenic variation.

A family with Sertoli-Leydig cell tumour, multinodular goiter, and DICER1 mutation

Background

DICER1 syndrome is an autosomal dominant tumour predisposition syndrome associated with a wide variety of cancerous and noncancerous conditions, including ovarian sex cord-stromal tumours and thyroid conditions, including multinodular goiter. The most common ovarian sex cord-stromal tumour associated with DICER1 syndrome is Sertoli-Leydig cell tumour, with germline DICER1 mutations present in more than 50% of cases. We present a case in which a patient in her late 30s was diagnosed with a Sertoli-Leydig cell tumour in the background of a strong family history of multinodular goiter and Sertoli-Leydig cell tumour with a germline mutation in DICER1.

Case Presentation

A 38-year-old woman with history of multinodular goiter was found to have stage iiic ovarian Sertoli-Leydig cell cancer after presenting with abdominal pain. She underwent multiple surgeries and chemotherapy. The patient developed rapid disease progression and died 7 months after diagnosis. Seven years earlier, a daughter had experienced the same disease and was found to have a germline DICER1 mutation. The mother had not undergone testing before her own diagnosis.

Summary

The co-occurrence of Sertoli-Leydig cell tumour and multinodular goiter is highly suggestive of DICER1 syndrome. The recognition of DICER1 syndrome within a family is essential for increased awareness and potential early recognition of complications. Most conditions associated with DICER1 syndrome occur in childhood, and most of the current screening recommendations are specific for childhood and young adulthood. Cancer risks and findings for the adult population are not as well defined. Clinicians who encounter DICER1 syndrome should review recommendations for genetic testing and surveillance and enrol patients in the DICER1 registry.

DICER1 Mutations in the Era of Expanding Integrative Clinical Sequencing in Pediatric Oncology

PURPOSE

DICER1 syndrome is a recently described inherited cancer predisposition syndrome caused by pathogenic variants in DICER1. With the recent increase in integrative clinical sequencing for pediatric patients with cancer, our understanding of the DICER1 syndrome continues to evolve, as new and rare pathogenic variants are reported. As the frequency of integrative clinical sequencing increases, discussions regarding challenges encountered in the interpretation of sequencing results are essential to continue to advance the field of cancer predisposition. The purpose of this work was to identify patients with somatic and/or germline DICER1 variants in our patient population and to discuss sequencing interpretation and the clinical recommendations that result from the integrative clinical sequencing results.

METHODS

Patients were enrolled in the PEDS-MIONCOSEQ study. This integrative clinical sequencing study includes paired tumor/normal whole-exome sequencing and tumor transcriptome sequencing. Patients identified as having DICER1 variants were included.

RESULTS

We report a DICER1 variant of unknown clinical significance in a patient with a highly unusual response to therapy. Two patients had diagnoses clarified once the integrative clinical sequencing revealing a DICER1 variant was available. We also discovered a patient with low-level DICER1 mosaicism and the challenges encountered in the sequencing interpretation for this patient. In addition to the sequencing data and result interpretation, this work also highlights testing and screening recommendations made to patients with DICER1 variants and their families on the basis of these results.

CONCLUSION

This work serves to extend the DICER1 phenotype and advance the utility of clinical integrative sequencing in the fields of pediatric oncology and cancer genetic predisposition.