KMT2D/MLL2 inactivation is associated with recurrence in adult-type granulosa cell tumors of the ovary. Nat Commun. 2018;9:2496. [PMID: 29950560 PMCID: PMC6021426 DOI: 10.1038/s41467-018-04950-x]

Ovarian Sex Cord-Stromal Neoplasms: An Overview of Molecular Events and How to Correlate Morphology With Molecular Findings

Since the discovery in 2009 that missence pathogenic variants/mutations in FOXL2 are extremely common in ovarian adult granulosa cell tumours, the last 2 decades have witnessed significant developments in our understanding of the molecular events underlying the pathogenesis of other ovarian sex cord-stromal tumours (SCSTs). In this review, we cover the molecular events in ovarian SCSTs and provide practical guidance to the reporting pathologist as to how and when molecular testing may be useful in diagnosis. We stress the need to correlate the morphology and molecular since most of the molecular events are not entirely specific for a particular tumour type and our knowledge is continually evolving with the elucidation of "new" molecular events. We also discuss that in some tumours, molecular testing is helpful in triaging the patient for genetic referral and germline testing since some of the molecular events may be germline in nature.

Sex Cord-Stromal Tumors of the Ovary: An Update and Review. Part II - Pure Sex Cord and Sex Cord-Stromal Tumors

We review the time honored but still frequently challenging features of ovarian sex cord-stromal tumors and also emphasize new developments, including unusual morphologic appearances that, despite the relative rarity of many of the tumors, result in a disproportionate number of differential diagnostic problems, variant immunohistochemical profiles, and specific molecular and syndromic associations. These neoplasms are also of historical interest as current knowledge is still based in significant part to the contributions of 2 giants of gynecologic pathology, Dr Robert Meyer and Dr. Robert E. Scully. In part I, we reviewed the pure ovarian stromal tumors. Now, in part II, we present the major clinical, pathologic, and genomic features of pure sex cord and sex cord-stromal tumors.

DNA alterations in ovarian adult granulosa cell tumours: A scoping review protocol

BACKGROUND

Identifying and describing molecular alterations in tumors has become common with the development of high-throughput sequencing. However, DNA sequencing in rare tumors, such as ovarian adult granulosa cell tumor (aGCT), often lacks statistical power due to the limited number of cases in each study. Questions regarding personalized treatment or prognostic biomarkers for recurrence or other malignancies therefore still need to be elucidated. This scoping review protocol aims to systematically map the current evidence and identify knowledge gaps regarding DNA alterations, actionable variations and prognostic biomarkers in aGCT.

METHODS

This scoping review will be conducted based on Arksey and O'Malley's methodological framework and later modifications by JBI Evidence Synthesis. The protocol complies with Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews. All original publications describing molecular alterations of aGCT will be included. The search will be performed in May 2024 in the following databases: MEDLINE (Ovid), Embase (Ovid), Web of Science Core Collection and Google Scholar (100-top ranked).

DISCUSSION

This scoping review will identify knowledge and gaps in the current understanding of the molecular landscape of aGCT, clinical trials on actionable variations and priorities for future research. As aGCT are rare, a possible limitation will be the small sample sizes and heterogenic study settings.

SCOPING REVIEW REGISTRATION

The review protocol is registered at Open Science Framework under https://doi.org/10.17605/OSF.IO/PX4MF.

A role for pH dynamics regulating transcription factor DNA binding selectivity

Intracellular pH (pHi) dynamics regulates diverse cell processes such as proliferation, dysplasia, and differentiation, often mediated by the protonation state of a functionally critical histidine residue in endogenous pH sensing proteins. How pHi dynamics can directly regulate gene expression and whether transcription factors can function as pH sensors has received limited attention. We tested the prediction that transcription factors with a histidine in their DNA binding domain (DBD) that forms hydrogen bonds with nucleotides can have pH-regulated activity, which is relevant to more than 85 transcription factors in distinct families, including FOX, KLF, SOX and MITF/Myc. Focusing on FOX family transcription factors, we used unbiased SELEX-seq to identify pH-dependent DNA binding motif preferences, then confirm pH-regulated binding affinities for FOXC2, FOXM1, and FOXN1 to a canonical FkhP DNA motif that are 2.5 to 7.5 greater at pH 7.0 compared with pH 7.5. For FOXC2, we also find greater activity for an FkhP motif at lower pHi in cells and that pH-regulated binding and activity are dependent on a conserved histidine (His122) in the DBD. RNA-seq with FOXC2 also reveals pH-dependent differences in enriched promoter motifs. Our findings identify pH-regulated transcription factor-DNA binding selectivity with relevance to how pHi dynamics can regulate gene expression for myriad cell behaviours.

Vaginal bleeding imitated rape in a 6-year old girl, a case report about granulosa cell tumor as a reason of peripheral precocious puberty

INTRODUCTION

Although female victims of sexual child abuse present with symptoms such as local pain and vaginal bleeding, however, before any definitive diagnosis a comprehensive physical examination along with a detailed history related to vaginal bleeding should be taken from the patient. Undoubtedly, we must not forget that only one of the causes of vaginal bleeding is rape. Therefore, before making a final diagnosis, other causes of this symptom must be carefully examined.

CASE PRESENTATION

The patient was a 6-years-old female who was hospitalized for notable generalized abdominal distention, acute lower abdomen pain associated with nausea and mild fever lasting 5 days progressively worsening, thelarche and vaginal bleeding. Ultrasound examination showed that multilocular-solid masses located in right side of abdomen which led to surgery and mass excision. Histopathology diagnosis was a juvenile granulosa cell tumor of the ovary.

DISCUSSION

Among the various causes of peripheral premature puberty, granulosa cell tumor (GCT) is rare but very important. Since in the two age groups - prepuberty and menopause - we don't expect to see vaginal bleeding, the occurrence of this disorder especially in association with breast enlargement in prepubertal group, need to appropriate imaging including pelvic ultrasound and bone age determination also laboratory data such as level of sex hormones and tumor markers to avoid misdiagnosis.

CONCLUSION

We report the case of a granulosa cell tumor patient with vaginal bleeding that a complete history and examination provides the right path to a diagnosis.

Somatic mutations of MLL4/COMPASS induce cytoplasmic localization providing molecular insight into cancer prognosis and treatment

Cancer genome sequencing consortiums have recently catalogued an abundance of somatic mutations, across a wide range of human cancers, in the chromatin-modifying enzymes that regulate gene expression. Defining the molecular mechanisms underlying the potentially oncogenic functions of these epigenetic mutations could serve as the basis for precision medicine approaches to cancer therapy. MLL4 encoded by the KMT2D gene highly mutated in a large number of human cancers, is a key histone lysine monomethyltransferase within the Complex of Proteins Associated with Set1 (COMPASS) family that regulates gene expression through enhancer function, potentially functioning as a tumor suppressor. We report that the KMT2D mutations which cause MLL4 protein truncation also alter MLL4's subcellular localization, resulting in loss-of-function in the nucleus and gain-of-function in the cytoplasm. We demonstrate that isogenic correction of KMT2D truncation mutation rescues the aberrant localization phenotype and restores multiple regulatory functions of MLL4, including COMPASS integrity/stabilization, histone H3K4 mono-methylation, enhancer activation, and therefore transcriptional regulation. Moreover, isogenic correction diminishes the sensitivity of KMT2D-mutated cancer cells to targeted metabolic inhibition. Using immunohistochemistry, we identified that cytoplasmic MLL4 is unique to the tissue of bladder cancer patients with KMT2D truncation mutations. Using a preclinical carcinogen model of bladder cancer in mouse, we demonstrate that truncated cytoplasmic MLL4 predicts response to targeted metabolic inhibition therapy for bladder cancer and could be developed as a biomarker for KMT2D-mutated cancers. We also highlight the broader potential for prognosis, patient stratification and treatment decision-making based on KMT2D mutation status in MLL4 truncation-relevant diseases, including human cancers and Kabuki Syndrome.

Update on Ovarian Sex Cord-Stromal Tumors

This article focuses on the recent advances in ovarian sex cord-stromal tumors, predominantly in the setting of their molecular underpinnings. The integration of genetic information with morphologic and immunohistochemical findings in this rare subset of tumors is of clinical significance from refining the diagnostic and prognostic stratifications to genetic counseling.

Comparative Tumor Microenvironment Analysis of Primary and Recurrent Ovarian Granulosa Cell Tumors

Adult-type granulosa cell tumors (aGCT) are rare ovarian sex cord tumors with few effective treatments for recurrent disease. The objective of this study was to characterize the tumor microenvironment (TME) of primary and recurrent aGCTs and to identify correlates of disease recurrence. Total RNA sequencing (RNA-seq) was performed on 24 pathologically confirmed, cryopreserved aGCT samples, including 8 primary and 16 recurrent tumors. After read alignment and quality-control filtering, DESeq2 was used to identify differentially expressed genes (DEG) between primary and recurrent tumors. Functional enrichment pathway analysis and gene set enrichment analysis was performed using "clusterProfiler" and "GSVA" R packages. TME composition was investigated through the analysis and integration of multiple published RNA-seq deconvolution algorithms. TME analysis results were externally validated using data from independent previously published RNA-seq datasets. A total of 31 DEGs were identified between primary and recurrent aGCTs. These included genes with known function in hormone signaling such as LHCGR and INSL3 (more abundant in primary tumors) and CYP19A1 (more abundant in recurrent tumors). Gene set enrichment analysis revealed that primarily immune-related and hormone-regulated gene sets expression was increased in recurrent tumors. Integrative TME analysis demonstrated statistically significant depletion of cancer-associated fibroblasts in recurrent tumors. This finding was confirmed in multiple independent datasets.

IMPLICATIONS

Recurrent aGCTs exhibit alterations in hormone pathway gene expression as well as decreased infiltration of cancer-associated fibroblasts, suggesting dual roles for hormonal signaling and TME remodeling underpinning disease relapse.

Systematic integration of protein-affecting mutations, gene fusions, and copy number alterations into a comprehensive somatic mutational profile

Somatic mutations occur as random genetic changes in genes through protein-affecting mutations (PAMs), gene fusions, or copy number alterations (CNAs). Mutations of different types can have a similar phenotypic effect (i.e., allelic heterogeneity) and should be integrated into a unified gene mutation profile. We developed OncoMerge to fill this niche of integrating somatic mutations to capture allelic heterogeneity, assign a function to mutations, and overcome known obstacles in cancer genetics. Application of OncoMerge to TCGA Pan-Cancer Atlas increased detection of somatically mutated genes and improved the prediction of the somatic mutation role as either activating or loss of function. Using integrated somatic mutation matrices increased the power to infer gene regulatory networks and uncovered the enrichment of switch-like feedback motifs and delay-inducing feedforward loops. These studies demonstrate that OncoMerge efficiently integrates PAMs, fusions, and CNAs and strengthens downstream analyses linking somatic mutations to cancer phenotypes.

The Oncogenic FOXL2 C134W Mutation Is a Key Driver of Granulosa Cell Tumors

Adult-type granulosa cell tumors (AGCT) are the most common type of malignant ovarian sex cord-stromal tumors. Most AGCTs carry the somatic variant c.402C>G (p.C134W) affecting the transcription factor FOXL2. Germline dominant variants in FOXL2 are responsible for blepharophimosis syndrome, which is characterized by underdevelopment of the eyelid. In this work, we generated a mouse model harboring the C134W variant of FOXL2 to evaluate in vivo the poorly understood oncogenic role of FOXL2. The mutation was dominant regarding eyelid hypoplasia, reminiscent of blepharophimosis syndrome. Interestingly, Foxl2+/C134W female mice had reduced fertility and developed AGCTs through a progression from abnormal ovaries with aberrant granulosa cells to ovaries with stromal hyperplasia and atypia and on to tumors in adut mice. The genes dysregulated in mouse AGCTs exhibited the hallmarks of cancer and were consistent with a gain-of-function of the mutated allele affecting TGFβ signaling. A comparison of these data with previous results on human AGCTs indicated similar deregulated pathways. Finally, a mutational analysis of mouse AGCT transcriptomic data suggested the absence of additional driver mutations apart from FOXL2-C134W. These results provide a clear in vivo example in which a single mutational hit triggers tumor development associated with profound transcriptomic alterations.

SIGNIFICANCE

A newly generated mouse model carrying a FOXL2 mutation characteristic of adult-type granulosa cell tumors shows that FOXL2 C134W shifts the transcriptome towards a signature of granulosa cell cancer and drives tumorigenesis.

Adult Granulosa Cell Tumor With Sarcomatous Transformation: A Case Study With Emphasis on Molecular Alterations

Adult granulosa cells tumors (AGCTs) are typically low-grade indolent tumors. On rare occasions, they undergo high-grade/sarcomatous transformation and behave aggressively. This transformation is postulated to occur as the result of acquired genetic alterations, some of which may be eligible for targeted therapy. Here we report a rare case of AGCT with sarcomatous transformation that harbored distinct molecular alterations from those typically seen with AGCTs supporting a molecularly driven approach to these malignancies. The patient is a 56-yr-old G3P3 woman with a history of multiple recurrences of ovarian AGCT for which the first diagnosis was made at the age of 25 when she was evaluated for infertility. The ovarian tumor displayed typical features of AGCT with low-grade, bland morphology. The first extraovarian spread of tumor involving the cul-de-sac was reported at the age of 39. After that, recurrences occurred every 2 to 3 yr with involvement of multiple anatomic sites and repeated surgical resections. At the age of 55 she developed a symptomatic recurrence in the pelvis and underwent resection of an isolated lesion (specimen 1) to no gross residual disease. Within 4 wk of resection she developed significant pelvic pain and imaging showed recurrence of the mass. Therefore, in 5 mo after the initial resection she underwent repeat excision of the lesion (specimen 2) and associated bowel. The sections from specimen 1 showed a biphasic morphology: a low-grade component with morphology and immunophenotype consistent with a typical AGCT and a high-grade spindle cell component with features consistent with a high-grade sarcoma. Specimen 2 featured a pure high-grade sarcoma characterized by coagulative tumor cell necrosis, readily recognizable mitoses, highly atypical cells with vesicular nuclei and prominent nucleoli. SF-1 positivity and the presence of FOXL2 C134W mutation in the sarcomatous component support the notion of transformation of typical AGCT. While detected TERT promoter C228T mutation may play a role in this process, we further identified genetic alterations affecting PI3K/AKT/mTOR pathway, including mutations in PIK3CA , PIK3R1 , AKT1 , and NF2 , which may also contribute to tumor progression/transformation. These findings provide rationale for molecular/pathway-based targeted therapy for patients with advanced AGCT.

Mismatch Repair Deficiency in Adult Granulosa Cell Tumors: an Immunohistochemistry-based Preliminary Study

OBJECTIVE

Adult granulosa cell tumors (AGCTs) are rare ovarian malignant neoplasms; their etiopathogenetic mechanisms remain largely unelucidated. Lately, defects in mismatch repair (MMR) have been implicated in the pathogenesis of AGCTs. Demonstration of MMR deficiency in these tumors can help identify patients potentially eligible for immune checkpoint inhibition therapy. The present study was done to explore the role of MMR deficiency in the etiopathogenesis of AGCTs.

METHODS

This was a retrospective study conducted on histopathologically confirmed AGCT cases. MMR protein expression was evaluated by immunohistochemistry (IHC) on tissue microarrays using an antibody panel of MSH2, MSH6, MLH1, and PMS2.

RESULTS

Of a total of 40 ovarian AGCTs evaluated for MMR deficiency, none demonstrated loss of expression of any of the 4 MMR proteins.

CONCLUSIONS

The results of our preliminary study show that there is no association between MMR deficiency with AGCT. Nevertheless, larger multicenter studies are needed to confirm or refute this observation.

Update on Ovarian Sex Cord-Stromal Tumors

This article focuses on the recent advances in ovarian sex cord-stromal tumors, predominantly in the setting of their molecular underpinnings. The integration of genetic information with morphologic and immunohistochemical findings in this rare subset of tumors is of clinical significance from refining the diagnostic and prognostic stratifications to genetic counseling.

Molecular assessment of testicular adult granulosa cell tumor demonstrates significant differences when compared to ovarian counterparts

Testicular adult granulosa cell tumor (AGCT) is a rare type of sex-cord stromal tumor that affects patients of a wide age range and has the potential for late metastasis. In the testis, the diagnosis of AGCTs often requires the exclusion of other more common types of sex-cord stromal tumors. Immunohistochemistry is of limited utility, being used mostly to confirm sex-cord lineage and to exclude other entities when morphology is not typical. Unlike ovarian AGCTs, which are molecularly homogeneous and harbor a specific activating FOXL2 mutation (c.7558C > T p.C134W) in >90% of cases, the molecular characteristics of testicular AGCTs remain largely unknown. In the current study, we analyzed 13 testicular AGCTs diagnosed at multiple institutions using massively parallel DNA sequencing to evaluate single nucleotide variants, copy number alterations, and structural variants. In all, 10/13 cases were sequenced successfully. Notably, the FOXL2 c.7558C > T (p.C134W) mutation was identified in only a single case (1/10, 10%). The remaining cases were molecularly heterogeneous, with largely nonrecurrent genetic variants. Putative driver events in individual cases included a well-characterized gain-of-function NRAS mutation, as well as inactivation of ATM and TP53, among others. The only highly recurrent finding was single copy loss of 22q (7/10 cases, 70%). Comparatively, the frequencies of FOXL2 c.7558C > T (p.C134W) and 22q loss in 12 metastatic ovarian AGCTs identified in our database were 92% (11/12) and 42% (5/12), respectively. The results of the present study suggest that testicular AGCTs are different from their ovarian counterparts in that they appear to be molecularly heterogeneous and only rarely harbor FOXL2 mutations.

The role of KMT2 gene in human tumors

Histone methylation plays a crucial role in the regulation of gene transcriptional expression, and aberration of methylation-modifying enzyme genes can lead to a variety of genetic diseases, including human cancers. The histone modified protein KMT2 (lysin methyltransferase) family are involved in cell proliferation, growth, development and differentiation through regulating gene expression, and are closely related with many blood cancers and solid tumors. In recent years, several studies have shown that mutations in the KMT2 gene occur frequently in a variety of human cancers and the mutation status of the KMT2 gene may be correlated with the occurrence, development and prognosis of some tumors. Research uncovering the clinical characteristics and molecular mechanisms of KMT2 mutation in human tumors will be helpful for early diagnosis and prognosis of tumors as well as drug development for targeted therapies.

Can adjuvant chemotherapy improve the prognosis of adult ovarian granulosa cell tumors?: A narrative review

ABSTRACT

Adult granulosa cell tumors (aGCTs) are rare ovarian neoplasms with a relatively favorable prognosis. They follow an indolent course, characterized by a prolonged natural history and a tendency to late recurrences, Around a quarter of patients develop recurrence and More than 70% of women with recurrence die from their disease, The percentage of patients received chemotherapy increases over time, whether adjuvant chemotherapy improve the prognosis of aGCTs is equivocal? The purpose of this review is to summarize the previously published evidence to evaluate whether adjuvant chemotherapy improve the prognosis of aGCTs to provide guidance for clinical practice. EMBASE, PubMed, Web of Science, WanFang Data and Chinese National Knowledge Infrastructure are searched up to December 2020, used the search strategy of ovar* and granulosa cell* and (tumor* or tumour* or malignan* or cancer* or carcinom* or neoplasm*) and chemotherapy. The screening process was conducted strictly based on inclusion and exclusion criteria. Clinical studies based on human including randomized controlled trial, quasi-randomised controlled trials, nonrandomised trials cohort study and case control study were included without restriction of time. The percentage of patients received chemotherapy increases over time, but the benefit of adjuvant chemotherapy is lack of high-grade evidence of prospective study, based on the current retrospective studies, we still do not have the evidence to confirm the survival benefit of adjuvant chemotherapy in early stage, advanced stage or recurrent aGCT with no residual tumor, but for inoperable disseminated disease or disease with suboptimal cytoreduction, adjuvant chemotherapy maybe an Optable options. Multinational prospective randomised controlled trials are urgently needed to validate the role of adjuvant chemotherapy. Further research on molecular mechanisms and developing novel targeted medicines may improve the survival of aGCTs.

Analysis of Non-Relapsed and Relapsed Adult Type Granulosa Cell Tumors Suggests Stable Transcriptomes during Tumor Progression

Adult-type granulosa cell tumor (AGCT) is a rare ovarian malignancy characterized by slow growth and hormonal activity. The prognosis of AGCT is generally favorable, but one-third of patients with low-stage disease experience a late relapse, and over half of them die of AGCT. To identify markers that would distinguish patients at risk for relapse, we performed Lexogen QuantSeq 3′ mRNA sequencing on formalin-fixed paraffin-embedded, archival AGCT tissue samples tested positive for the pathognomonic Forkhead Box L2 (FOXL2) mutation. We compared the transcriptomic profiles of 14 non-relapsed archival primary AGCTs (follow-up time 17–26 years after diagnosis) with 13 relapsed primary AGCTs (follow-up time 1.7–18 years) and eight relapsed tumors (follow-up time 2.8–18.9 years). Non-relapsed and relapsed primary AGCTs had similar transcriptomic profiles. In relapsed tumors three genes were differentially expressed: plasmalemma vesicle associated protein (PLVAP) was upregulated (p = 0.01), whereas argininosuccinate synthase 1 (ASS1) (p = 0.01) and perilipin 4 (PLIN4) (p = 0.02) were downregulated. PLVAP upregulation was validated using tissue microarray RNA in situ hybridization. In our patient cohort with extremely long follow-up, we observed similar gene expression patterns in both primary AGCT groups, suggesting that relapse is not driven by transcriptomic changes. These results reinforce earlier findings that molecular markers do not predict AGCT behavior or risk of relapse.

Integrated analysis of ovarian juvenile granulosa cell tumors reveals distinct epigenetic signatures and recurrent TERT rearrangements

PURPOSE

Adult granulosa cell tumor (AGCT) is characterized by the somatic FOXL2 p.C134W mutation, and recurrences have been associated with TERT promoter and KMT2D-truncating mutations. Conversely, the molecular underpinnings of the rare juvenile granulosa cell tumor (JGCT) have not been well elucidated. To this end, we applied a tumor-only integrated approach to investigate the genomic, transcriptomic, and epigenomic landscape of 31 JGCTs to identify putative oncogenic drivers.

EXPERIMENTAL DESIGN

Multipronged analyses of 31 JGCTs were performed utilizing a clinically validated next-generation sequencing (NGS)-panel targeting 580 cancer-related genes for genomic interrogation, in addition to targeted RNA NGS for transcriptomic exploration. Genome-wide DNA methylation profiling was conducted using an Infinium Methylation EPIC array targeting 866,562 CpG methylation sites.

RESULTS

We identified frequent KMT2C-truncating mutations along with other mutated genes implicated in the switch/sucrose nonfermentable (SWI/SNF) chromatin remodeling complex, in addition to previously reported hotspot AKT1 and DICER1 mutations. Targeted transcriptome sequencing revealed recurrent TERT rearrangements (13%) involving partners CLPTM1L or DROSHA, and differential gene expression analysis showed FGFR1 upregulation in the TERT non-rearranged JGCTs under direct promoter control. Genome-wide DNA methylation rendered a clear delineation between AGCTs and JGCTs at the epigenomic level further supporting its diagnostic utility in distinguishing among these tumors.

CONCLUSIONS

This is the largest comprehensive molecular study of JGCTs, where we further expand our current understanding of JGCT pathogenesis and demonstrate putative oncogenic drivers and TERT rearrangements in a subset of tumors. Our findings further offer insights into possible targeted therapies in a rare entity.

Cytologic features of sex cord-stromal tumors in women

BACKGROUND

Gynecologic sex cord-stromal tumors (SCSTs) arise from sex cords of the embryonic gonad and may display malignant behavior. We describe the cytomorphologic features of SCSTs in females, including adult and juvenile granulosa cell tumors (AGCTs and JGCTs), Sertoli-Leydig cell tumors (SLCTs), and steroid cell tumors (SCTs).

METHODS

We retrieved available cytology slides from females with a histologic diagnosis of sex cord-stromal tumor between 2009 and 2020 from institutional archives and reviewed their cytoarchitectural features.

RESULTS

There were 25, 2, 2, and 1 cytology specimens from 19, 2, 2, and 1 patients (aged 7-90 years, median 57 years) with AGCT, JGCT, SLCT, and SCT, respectively. Features common to all SCSTs included 3-dimensional groups, rosettes, rare papillary fragments, abundant single cells and naked nuclei. Rosettes and a streaming appearance of cell groups were only seen in AGCTs, which also rarely featured eosinophilic hyaline globules and metachromatic stroma. AGCTs exhibited high nuclear:cytoplasmic (N:C) ratios, with mild nuclear pleomorphism, uniform nuclei with finely granular chromatin, nuclear grooves and small nucleoli; in contrast, other SCSTs lacked rosettes and nuclear grooves and had generally lower N:C ratios, greater nuclear pleomorphism, coarse chromatin and more abundant cytoplasm. Mitotic figures, necrosis, and inflammation were rarely identified.

CONCLUSIONS

AGCTs show cytomorphologic features that are distinct from those of other SCSTs. Careful evaluation of the cytological features and ancillary studies (eg, immunochemistry for FOXL2, inhibin and calretinin, or sequencing for FOXL2 mutations) can aid in the accurate diagnosis of these tumors.

Prevalence of predictive biomarkers in a large cohort of molecularly defined adult-type ovarian granulosa cell tumors

OBJECTIVE

The objective of this study was to determine the prevalence of predictive biomarkers associated with FDA-approved therapies in molecularly defined adult-type ovarian granulosa cell tumors (aGCTs).

METHODS

We performed a retrospective cross-sectional cohort study of tumor profiles using the inclusion criteria of molecularly defined (FOXL2 c.C402G positive) aGCTs previously sequenced at Foundation Medicine, Inc. The dataset included coding variants for up to 406 genes, microsatellite instability, tumor mutational burden, and genomic loss of heterozygosity (gLOH). PD-L1 expression was determined using the tumor proportion score, as measured using the DAKO 22C3 immunohistochemistry assay.

RESULTS

423 tumor profiles met inclusion criteria. The median age at the time of sample submission was 57 years (interquartile range 48-65). The mean tumor mutational burden was 1.8 mutations per megabase (range 0-8.8). No tumors exhibited microsatellite instability, and none were gLOH-High (≥16%). Sixty-seven tumors had PD-L1 expression measurement, and 94% were negative. Potentially actionable variants including MTAP deletion (12/173, 5.8%) and activating PIK3CA mutations (23/423, 5.4%) were identified. TP53-mutated aGCT had a higher tumor mutational burden (mean 2.4 mut/Mb, 95% CI 1.7-3.0 mut/Mb vs mean 1.7 mut/Mb, 95% CI 1.5-1.9 mut/Mb; P = .02) and higher gLOH score (mean 4.4%, 95% CI 2.7-6.1% vs mean 1.4%, 95% CI 1.2-1.6%; P = .002) than TP53 non-mutated tumors.

CONCLUSIONS

No women with molecularly defined aGCT in this large cohort would be eligible for FDA-approved pembrolizumab based on either microsatellite instability or high tumor mutational burden. TP53 mutation identified a subset of this tumor type with distinct molecular features. The development of precision treatment options remains a critical unmet need for this rare disease.

The MLL3/4 H3K4 methyltransferase complex in establishing an active enhancer landscape

Enhancers are cis-regulatory elements that play essential roles in tissue-specific gene expression during development. Enhancer function in the expression of developmental genes requires precise regulation, while deregulation of enhancer function could be the main cause of tissue-specific cancer development. MLL3/KMT2C and MLL4/KMT2D are two paralogous histone modifiers that belong to the SET1/MLL (also named COMPASS) family of lysine methyltransferases and play critical roles in enhancer-regulated gene activation. Importantly, large-scale DNA sequencing studies have revealed that they are amongst the most frequently mutated genes associated with human cancers. MLL3 and MLL4 form identical multi-protein complexes for modifying mono-methylation of histone H3 lysine 4 (H3K4) at enhancers, which together with the p300/CBP-mediated H3K27 acetylation can generate an active enhancer landscape for long-range target gene activation. Recent studies have provided a better understanding of the possible mechanisms underlying the roles of MLL3/MLL4 complexes in enhancer regulation. Moreover, accumulating studies offer new insights into our knowledge of the potential role of MLL3/MLL4 in cancer development. In this review, we summarize recent evidence on the molecular mechanisms of MLL3/MLL4 in the regulation of active enhancer landscape and long-range gene expression, and discuss their clinical implications in human cancers.

Cancer-epigenetic function of the histone methyltransferase KMT2D and therapeutic opportunities for the treatment of KMT2D-deficient tumors

Epigenetic mechanisms are central to understanding the molecular basis underlying tumorigenesis. Aberrations in epigenetic modifiers alter epigenomic landscapes and play a critical role in tumorigenesis. Notably, the histone lysine methyltransferase KMT2D (a COMPASS/ Set1 family member; also known as MLL4, ALR, and MLL2) is among the most frequently mutated genes in many different types of cancer. Recent studies have demonstrated how KMT2D loss induces abnormal epigenomic reprograming and rewires molecular pathways during tumorigenesis. These findings also have clinical and therapeutic implications for cancer treatment. In this review, we summarize recent advances in understanding the role of KMT2D in regulating tumorigenesis and discuss therapeutic opportunities for the treatment of KMT2D-deficient tumors.

Adult-type granulosa cell tumor of the ovary: a FOXL2-centric disease

Adult-type granulosa cell tumors (aGCTs) account for 90% of malignant ovarian sex cord-stromal tumors and 2-5% of all ovarian cancers. These tumors are usually diagnosed at an early stage and are treated with surgery. However, one-third of patients relapse between 4 and 8 years after initial diagnosis, and there are currently no effective treatments other than surgery for these relapsed patients. As the majority of aGCTs (>95%) harbor a somatic mutation in FOXL2 (c.C402G; p.C134W), the aim of this study was to identify genetic mutations besides FOXL2 C402G in aGCTs that could explain the clinical diversity of this disease. Whole-genome sequencing of 10 aGCTs and their matched normal blood was performed to identify somatic mutations. From this analysis, a custom amplicon-based panel was designed to sequence 39 genes of interest in a validation cohort of 83 aGCTs collected internationally. KMT2D inactivating mutations were present in 10 of 93 aGCTs (10.8%), and the frequency of these mutations was similar between primary and recurrent aGCTs. Inactivating mutations, including a splice site mutation in candidate tumor suppressor WNK2 and nonsense mutations in PIK3R1 and NLRC5, were identified at a low frequency in our cohort. Missense mutations were identified in cell cycle-related genes TP53, CDKN2D, and CDK1. From these data, we conclude that aGCTs are comparatively a homogeneous group of tumors that arise from a limited set of genetic events and are characterized by the FOXL2 C402G mutation. Secondary mutations occur in a subset of patients but do not explain the diverse clinical behavior of this disease. As the FOXL2 C402G mutation remains the main driver of this disease, progress in the development of therapeutics for aGCT would likely come from understanding the functional consequences of the FOXL2 C402G mutation.

The clinical efficacy and safety of single-agent pembrolizumab in patients with recurrent granulosa cell tumors of the ovary: a case series from a phase II basket trial

Background Treatment of recurrent, unresectable granulosa cell tumor (GCT) of the ovary can be challenging. Given the rarity of the tumor, alternative therapies have been difficult to evaluate in large prospective clinical trials. Currently, to our knowledge, there are no reports of the use of immune checkpoint inhibitors in GCT patients. Here, we present a case series of GCT patients treated with pembrolizumab who were enrolled in a phase II basket trial in advanced, rare solid tumors (ClinicalTrials.gov: NCT02721732). Cases We identified 5 patients with recurrent GCT (4 adult and 1 juvenile type); they had an extensive history of systemic therapy at study enrollment (range, 3-10), with most regimens resulting in less than 12 months of disease control. Pembrolizumab was administered in these patients, as per trial protocol. Although there were no objective responses according to the irRECIST guidelines, 2 patients with adult-type GCT experienced disease control for ≥ 12 months (565 and 453 days). In one, pembrolizumab represented the longest duration of disease control compared to prior lines of systemic therapy (565 days vs. 13 months). In the other, pembrolizumab was the second longest systemic therapy associated with disease control (453 days vs. 22 months) compared to prior lines of therapy. In this patient, pembrolizumab was discontinued following withdrawal of consent. PD-L1 expression was not observed in any baseline tumor samples. Pembrolizumab was well tolerated, with no grade 3 or 4 treatment-related adverse events. Conclusions Although our results do not support the routine use of pembrolizumab monotherapy in unselected GCT patients, some patients with adult-type GCT may derive a clinical benefit, with a low risk of toxicity. Future studies should investigate the role of immunotherapy and predictors of clinical benefit in this patient population.

Genomic profiling of primary and recurrent adult granulosa cell tumors of the ovary

Adult-type granulosa cell tumor (aGCT) is a rare malignant ovarian sex cord-stromal tumor, harboring recurrent FOXL2 c.C402G/p.C134W hotspot mutations in 97% of cases. These tumors are considered to have a favorable prognosis, however aGCTs have a tendency for local spread and late recurrences, which are associated with poor survival rates. We sought to determine the genetic alterations associated with aGCT disease progression. We subjected primary non-recurrent aGCTs (n = 7), primary aGCTs that subsequently recurred (n = 9) and their matched recurrences (n = 9), and aGCT recurrences without matched primary tumors (n = 10) to targeted massively parallel sequencing of ≥410 cancer-related genes. In addition, three primary non-recurrent aGCTs and nine aGCT recurrences were subjected to FOXL2 and TERT promoter Sanger sequencing analysis. All aGCTs harbored the FOXL2 C134W hotspot mutation. TERT promoter mutations were found to be significantly more frequent in recurrent (18/28, 64%) than primary aGCTs (5/19, 26%, p = 0.017). In addition, mutations affecting TP53, MED12, and TET2 were restricted to aGCT recurrences. Pathway annotation of altered genes demonstrated that aGCT recurrences displayed an enrichment for genetic alterations affecting cell cycle pathway-related genes. Analysis of paired primary and recurrent aGCTs revealed that TERT promoter mutations were either present in both primary tumors and matched recurrences or were restricted to the recurrence and absent in the respective primary aGCT. Clonal composition analysis of these paired samples further revealed that aGCTs display intra-tumor genetic heterogeneity and harbor multiple clones at diagnosis and relapse. We observed that in a subset of cases, recurrences acquired additional genetic alterations not present in primary aGCTs, including TERT, MED12, and TP53 mutations and CDKN2A/B homozygous deletions. Albeit harboring relatively simple genomes, our data provide evidence to suggest that aGCTs are genetically heterogeneous tumors and that TERT promoter mutations and/or genetic alterations affecting other cell cycle-related genes may be associated with disease progression and recurrences.

Comparative genomics of high grade neuroendocrine carcinoma of the cervix

In order to improve treatment selection for high grade neuroendocrine carcinomas of the cervix (NECC), we performed a comparative genomic analysis between this rare tumor type and other cervical cancer types, as well as extra-cervical neuroendocrine small cell carcinomas of the lung and bladder. We performed whole exome sequencing on fresh-frozen tissue from 15 NECCs and matched normal tissue. We then identified mutations and copy number variants using standard analysis pipelines. Published mutation tables from cervical cancers and extra-cervical small cell carcinomas were used for comparative analysis. Descriptive statistical methods were used and a two-sided threshold of P < .05 was used for significance. In the NECC cohort, we detected a median of 1.7 somatic mutations per megabase (range 1.0-20.9). PIK3CA p.E545K mutations were the most frequency observed oncogenic mutation (4/15 tumors, 27%). Activating MAPK pathway mutations in KRAS (p.G12D) and GNAS (p.R201C) co-occurred in two tumors (13%). In total we identified PI3-kinase or MAPK pathway activating mutations in 67% of NECC. When compared to NECC, lung and bladder small cell carcinomas exhibited a statistically significant higher rate of coding mutations (P < .001 for lung; P = .001 for bladder). Mutation of TP53 was uncommon in NECC (13%) and was more frequent in both lung (103 of 110 tumors [94%], P < .001) and bladder (18 of 19 tumors [95%], P < .001) small cell carcinoma. These comparative genomics data suggest that NECC may be genetically more similar to common cervical cancer subtypes than to extra-cervical small cell neuroendocrine carcinomas of the lung and bladder. These results may have implications for the selection of cytotoxic and targeted therapy regimens for this rare disease.

Whole Genome Analysis of Ovarian Granulosa Cell Tumors Reveals Tumor Heterogeneity and a High-Grade TP53-Specific Subgroup

Adult granulosa cell tumors (AGCTs) harbor a somatic FOXL2 c.402C>G mutation in ~95% of cases and are mainly surgically removed due to limited systemic treatment effect. In this study, potentially targetable genomic alterations in AGCTs were investigated by whole genome sequencing on 46 tumor samples and matched normal DNA. Copy number variant (CNV) analysis confirmed gain of chromosome 12 and 14, and loss of 22. Pathogenic TP53 mutations were identified in three patients with highest tumor mutational burden and mitotic activity, defining a high-grade AGCT subgroup. Within-patient tumor comparisons showed 29-80% unique somatic mutations per sample, suggesting tumor heterogeneity. A higher mutational burden was found in recurrent tumors, as compared to primary AGCTs. FOXL2-wildtype AGCTs harbored DICER1, TERT(C228T) and TP53 mutations and similar CNV profiles as FOXL2-mutant tumors. Our study confirms that absence of the FOXL2 c.402C>G mutation does not exclude AGCT diagnosis. The lack of overlapping variants in targetable cancer genes indicates the need for personalized treatment for AGCT patients.

FOXL2 homozygous genotype and chromosome instability are associated with recurrence in adult granulosa cell tumors of the ovary

Introduction: Adult granulosa cell tumors (aGCTs) are extremely rare tumors characterized by the presence of the single missense mutation (c.402 C>G, p. C134W) in the FOXL2 gene. These tumors are frequently associated with a slow, indolent disease progression and a high probability of aggressive tumor recurrence. Hence, the identification of molecular markers that are predictive of recurrence and/or aggressive behavior would be a great asset in the management of aGCT. The present study focused on the influence of the FOXL2 genotype (heterozygous or homozygous) and copy number variations (CNVs) in recurrence by comparing the primary tumor with recurrent lesions in the same patient. We performed array comparative genomic hybridization (CGH) experiments and FOXL2 genotyping by allelic discrimination on 40 tumor samples. Results and Discussion: In array CGH results of recurrent tumors, few samples presented the multiple chromosome losses and gains characteristic of chromosome instability (CIN). We also observed that three recurrent tumors and one primary tumor appeared to be homozygous for the FOXL2 c.402C>G mutation. Interestingly, the homozygous FOXL2 genotype was correlated with a shorter time to relapse. A change in the FOXL2 genotype in cases of recurrence was correlated with the appearance of CIN. Conclusion: Despite the small number of matching primary and recurrent tumors analyzed here, the present study is the first to have shown that the FOXL2 homozygous genotype and CIN are prevalent in recurrent aGCTs. The two mechanisms are probably linked, and both almost certainly have a role in the molecular transformation of aGCTs.

Tumor-infiltrating lymphocyte-derived MLL2 independently predicts disease-free survival for patients with early-stage oral squamous cell carcinoma

BACKGROUND

MLL2 (mixed-lineage leukemia 2) is recognized as an essential role in regulating histone 3 lysine 4 tri-methylation (H3K4me3) in mammalian cells. It is frequently mutated to promote developmental diseases and tumor initiation. However, the expression pattern of MLL2 and its clinical significance for patients with early-stage oral squamous cell carcinoma (OSCC) remain totally unknown.

METHODS

Eighty-five samples of primary early-stage OSCC were enrolled in this retrospective study, and immunohistochemistry (IHC) was performed to detect the spatial pattern of MLL2. The diagnostic and prognostic value of MLL2 were assessed.

RESULTS

MLL2 was widely expressed in tumor cells (TCs), fibroblast-like cells (FLCs), and tumor-infiltrating lymphocytes (TILs), both in tumor center and invasive tumor front, and showed no distributive heterogeneity. Moreover, regardless of cell types and microlocalization, patients with high expressed MLL2 had increased depth invasion of tumor (DOI). Besides, upregulation of MLL2^TC and MLL2^TIL in tumor center were both associated with poor differentiation, but showed no correlation with tumor growth with comparable Ki-67 levels. Prognostic analysis indicated that early-stage OSCC patients with enhanced MLL2^TIL in invasive tumor front were susceptible to occur postoperative metastasis and recurrence. Indeed, patients with higher expressed MLL2^TIL showed shorter overall survival (OS) and disease-free survival (DFS), and MLL2^TIL in invasive tumor front was an independent risk factor of DFS.

CONCLUSION

TIL-derived MLL2 in invasive tumor front was an independent prognostic factor of DFS for early-stage OSCC patients.

MiRNA-217 accelerates the proliferation and migration of bladder cancer via inhibiting KMT2D

To uncover the biological function of miRNA-217 in the progression of bladder cancer and the underlying mechanism. Potential miRNAs binding KMT2D were predicted through online bioinformatics. Their expression levels in bladder cancer tissues and adjacent ones were determined. Through Pearson correlation analysis and survival analysis, the most potential miRNA candidate (miRNA-217) that targets and regulates KMT2D in bladder cancer was selected. Subsequently, expression levels of miRNA-217 and KMT2D in non-muscle invasive bladder cancer (NMIBC) and muscle invasive bladder cancer (MIBC) were detected. MiRNA-217 level in bladder cancer cell lines was determined as well. The interaction between KMT2D and miRNA-217 was verified by dual-luciferase reporter gene assay. Finally, regulatory effect of miRNA-217 on viability and migration in T24 and UMUC-3 cells were investigated. Five potential candidates that were upstream genes binding KMT2D were searched by bioinformatics. Among them, miRNA-217 was remarkably upregulated in bladder cancer tissues and closely linked to poor prognosis of affected patients. Moreover, dual-luciferase reporter gene assay verified the interaction between miRNA-217 and KMT2D. MiRNA-217 was able to downregulate mRNA and protein levels of KMT2D. Furthermore, knockdown of miRNA-217 attenuated viability and migration in bladder cancer cells. MiRNA-217 accelerates proliferative and migratory abilities in bladder cancer via inhibiting the level of tumor suppressor KMT2D, thereafter leading to the poor prognosis in bladder cancer patients.

Targeting epigenetic machinery: Emerging novel allosteric inhibitors

Epigenetics has emerged as an extremely exciting fast-growing area of biomedical research in post genome era. Epigenetic dysfunction is tightly related with various diseases such as cancer and aging related degeneration, potentiating epigenetics modulators as important therapeutics targets. Indeed, inhibitors of histone deacetylase and DNA methyltransferase have been approved for treating blood tumor malignancies, whereas inhibitors of histone methyltransferase and histone acetyl-lysine recognizer bromodomain are in clinical stage. However, it remains a great challenge to discover potent and selective inhibitors by targeting catalytic site, as the same subfamily of epigenetic enzymes often share high sequence identity and very conserved catalytic core pocket. It is well known that epigenetic modifications are usually carried out by multi-protein complexes, and activation of catalytic subunit is often tightly regulated by other interactive protein component, especially in disease conditions. Therefore, it is not unusual that epigenetic complex machinery may exhibit allosteric regulation site induced by protein-protein interactions. Targeting allosteric site emerges as a compelling alternative strategy to develop epigenetic drugs with enhanced druggability and pharmacological profiles. In this review, we highlight recent progress in the development of allosteric inhibitors for epigenetic complexes through targeting protein-protein interactions. We also summarized the status of clinical applications of those inhibitors. Finally, we provide perspectives of future novel allosteric epigenetic machinery modulators emerging from otherwise undruggable single protein target.

KMT2D deficiency enhances the anti-cancer activity of L48H37 in pancreatic ductal adenocarcinoma

BACKGROUND

Novel therapeutic strategies are urgently needed for patients with a delayed diagnosis of pancreatic ductal adenocarcinoma (PDAC) in order to improve their chances of survival. Recent studies have shown potent anti-neoplastic effects of curcumin and its analogues. In addition, the role of histone methyltransferases on cancer therapeutics has also been elucidated. However, the relationship between these two factors in the treatment of pancreatic cancer remains unknown. Our working hypothesis was that L48H37, a novel curcumin analog, has better efficacy in pancreatic cancer cell growth inhibition in the absence of histone-lysine N-methyltransferase 2D (KMT2D).

AIM

To determine the anti-cancer effects of L48H37 in PDAC, and the role of KMT2D on its therapeutic efficacy.

METHODS

The viability and proliferation of primary (PANC-1 and MIA PaCa-2) and metastatic (SW1990 and ASPC-1) PDAC cell lines treated with L48H37 was determined by CCK8 and colony formation assay. Apoptosis, mitochondrial membrane potential (MMP), reactive oxygen species (ROS) levels, and cell cycle profile were determined by staining the cells with Annexin-V/7-AAD, JC-1, DCFH-DA, and PI respectively, as well as flow cytometric acquisition. In vitro migration was assessed by the wound healing assay. The protein and mRNA levels of relevant factors were analyzed using Western blotting, immunofluorescence and real time-quantitative PCR. The in situ expression of KMT2D in both human PDAC and paired adjacent normal tissues was determined by immunohistochemistry. In vivo tumor xenografts were established by injecting nude mice with PDAC cells. Bioinformatics analyses were also conducted using gene expression databases and TCGA.

RESULTS

L48H37 inhibited the proliferation and induced apoptosis in SW1990 and ASPC-1 cells in a dose- and time-dependent manner, while also reducing MMP, increasing ROS levels, arresting cell cycle at the G2/M stages and activating the endoplasmic reticulum (ER) stress-associated protein kinase RNA-like endoplasmic reticulum kinase/eukaryotic initiation factor 2α/activating transcription factor 4 (ATF4)/CHOP signaling pathway. Knocking down ATF4 significantly upregulated KMT2D in PDAC cells, and also decreased L48H37-induced apoptosis. Furthermore, silencing KMT2D in L48H37-treated cells significantly augmented apoptosis and the ER stress pathway, indicating that KMT2D depletion is essential for the anti-neoplastic effects of L48H37. Administering L48H37 to mice bearing tumors derived from control or KMT2D-knockdown PDAC cells significantly decreased the tumor burden. We also identified several differentially expressed genes in PDAC cell lines expressing very low levels of KMT2D that were functionally categorized into the extrinsic apoptotic signaling pathway. The KMT2D high- and low-expressing PDAC patients from the TCGA database showed similar survival rates,but higher KMT2D expression was associated with poor tumor grade in clinical and pathological analyses.

CONCLUSION

L48H37 exerts a potent anti-cancer effect in PDAC, which is augmented by KMT2D deficiency.

Genomic analysis of recurrences and high-grade forms of polymorphous adenocarcinoma

AIMS

Polymorphous adenocarcinoma (PAC) usually follows an indolent course, but some cases may show recurrences and high-grade features. The genetic events associated with recurrences and high-grade versions are yet to be defined. Our aim was to determine the genetic underpinning of recurrent PACs of the salivary gland and the repertoire of somatic genetic alterations in cases with high-grade histology.

METHODS AND RESULTS

Four PACs from three patients, including one case with matching primary and recurrent tumours, one de-novo high-grade PAC, and a PAC that transformed to a high-grade tumour following multiple recurrences, were subjected to targeted sequencing (Memorial Sloan Kettering Mutation Profiling of Actionable Cancer Targets assay) or whole-exome sequencing. Both matching primary and recurrent tumours, and the de-novo high-grade PAC, harboured clonal PRKD1 E710D hotspot mutations, whereas the PAC that underwent high-grade transformation upon recurrence, which was wild-type for PRKD1, harboured a PRKD2 rearrangement. The PACs analysed here also harboured mutations targeting cancer genes such as PIK3CA, SETD2, ARID1A, and NOTCH2. A clonal decomposition analysis of the matching primary and recurrent PACs revealed that a minor subclone from the primary tumour became dominant in the recurrent tumour following a clonal selection evolutionary pattern.

CONCLUSIONS

Our findings demonstrate that recurrent and high-grade PACs are underpinned by PRKD1 E710D hotspot mutations or PRKD2 rearrangements, and that recurrences of PACs may stem from the selection of pre-existing subclones in the primary tumour.