Osteosarcoma PDX-Derived Cell Line Models for Preclinical Drug Evaluation Demonstrate Metastasis Inhibition by Dinaciclib through a Genome-Targeted Approach

PURPOSE

Models to study metastatic disease in rare cancers are needed to advance preclinical therapeutics and to gain insight into disease biology. Osteosarcoma is a rare cancer with a complex genomic landscape in which outcomes for patients with metastatic disease are poor. As osteosarcoma genomes are highly heterogeneous, multiple models are needed to fully elucidate key aspects of disease biology and to recapitulate clinically relevant phenotypes.

EXPERIMENTAL DESIGN

Matched patient samples, patient-derived xenografts (PDX), and PDX-derived cell lines were comprehensively evaluated using whole-genome sequencing and RNA sequencing. The in vivo metastatic phenotype of the PDX-derived cell lines was characterized in both an intravenous and an orthotopic murine model. As a proof-of-concept study, we tested the preclinical effectiveness of a cyclin-dependent kinase inhibitor on the growth of metastatic tumors in an orthotopic amputation model.

RESULTS

PDXs and PDX-derived cell lines largely maintained the expression profiles of the patient from which they were derived despite the emergence of whole-genome duplication in a subset of cell lines. The cell lines were heterogeneous in their metastatic capacity, and heterogeneous tissue tropism was observed in both intravenous and orthotopic models. Single-agent dinaciclib was effective at dramatically reducing the metastatic burden.

CONCLUSIONS

The variation in metastasis predilection sites between osteosarcoma PDX-derived cell lines demonstrates their ability to recapitulate the spectrum of the disease observed in patients. We describe here a panel of new osteosarcoma PDX-derived cell lines that we believe will be of wide use to the osteosarcoma research community.

Mitochondrial uncoupler and retinoic acid synergistically induce differentiation and inhibit proliferation in neuroblastoma

Neuroblastoma is a leading cause of death in childhood cancer cases. Unlike adult malignancies, which typically develop from aged cells through accumulated damage and mutagenesis, neuroblastoma originates from neural crest cells with disrupted differentiation. This distinct feature provides novel therapeutic opportunities beyond conventional cytotoxic methods. Previously, we reported that the mitochondrial uncoupler NEN (niclosamide ethanolamine) activated mitochondria respiration to reprogram the epigenome, promoting neuronal differentiation. In the current study, we further combine NEN with retinoic acid (RA) to promote neural differentiation both in vitro and in vivo. The treatment increased the expression of RA signaling and neuron differentiation-related genes, resulting in a global shift in the transcriptome towards a more favorable prognosis. Overall, these results suggest that the combination of a mitochondrial uncoupler and the differentiation agent RA is a promising therapeutic strategy for neuroblastoma.

Clinical Features of SARS-CoV-2 Infection During Pregnancy and Associated Placental Pathologies

SUMMARY

We reviewed the clinicopathologic findings of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-exposed placentas at our institution. We identified patients diagnosed with SARS-CoV-2 during pregnancy (March-October 2020). Clinical data included gestational age at diagnosis and delivery and maternal symptoms. Hematoxylin and eosin slides were reviewed for maternal vascular malperfusion, fetal vascular malperfusion, chronic villitis, amniotic fluid infection, intervillous thrombi, fibrin deposition, and infarction. Immunohistochemistry (IHC) for coronavirus spike protein and RNA in situ hybridization (ISH) for SARS-CoV-2 was performed on a subset of blocks. A review of placentas from age-matched patients received March-October 2019 was conducted as a comparison cohort. A total of 151 patients were identified. Placentas in the 2 groups were similar in weight for gestational age and had similar rates of maternal vascular malperfusion, fetal vascular malperfusion, amniotic fluid infection, intervillous thrombi, fibrin deposition, and infarction. Chronic villitis was the only significantly different pathologic finding between cases and controls (29% of cases showed chronic villitis vs. 8% of controls, P <0.001). Overall, 146/151 (96.7%) cases were negative for IHC and 129/133 (97%) cases were negative for RNA ISH. There were 4 cases that stained positively for IHC/ISH, 2 of which showed massive perivillous fibrin deposition, inflammation, and decidual arteriopathy. Coronavirus disease 2019 (COVID-19)-positive patients were more likely to self-identify as Hispanic and more likely to have public health insurance. Our data suggests SARS-CoV-2 exposed placentas that stain positively for SARS-CoV-2 show abnormal fibrin deposition, inflammatory changes, and decidual arteriopathy. The group of patients with clinical COVID-19 are more likely to show chronic villitis. IHC and ISH evidence of viral infection is rare.

Characterizing Lymphovascular Invasion in Pediatric and Adolescent Malignant Ovarian Nongerminomatous Germ Cell Tumors: A Report from the Children's Oncology Group

BACKGROUND

Lymphovascular invasion (LVI) has been identified as a poor prognostic factor for a variety of tumors; however, its significance in malignant ovarian germ cell tumors (MOGCT) in pediatric and adolescent patients is not well described. We aim to clarify the significance of LVI in the subset of patients with nongerminomatous MOGCT.

METHODS

Records of patients 0-20 years of age with MOGCT enrolled on Children's Oncology Group study AGCT0132 were reviewed. Patients with documented presence or absence of LVI in either institutional or central review pathology reports were included.

RESULTS

Of 130 patients with MOGCTs, 83 patients had of the presence or absence of LVI documented in their pathology report. 42/83 patients (50.6%) were found to have LVI present. The estimated odds of having LVI was higher in patients with stage II and III disease, 11 years and older and with the presence of choriocarcinoma. Event-free survival (EFS) and overall survival (OS) remained high in patients with LVI. Approximately 50% of patients with a documented LVI status in either institutional pathology report or central review were found to have LVI.

CONCLUSIONS

The presence of LVI was higher in tumors with adverse risk factors including higher stage and age greater than 11 years. While LVI was not associated with EFS or OS in the intermediate risk group, further work is necessary to determine the effect of LVI on long-term disease-free survival. We, therefore, recommend routinely incorporating LVI status into institutional pathology reports for pediatric and adolescent patients with MOGCT.

LEVEL OF EVIDENCE

III.

Clinicopathologic Features of IDEDNIK (MEDNIK) Syndrome in a Term Infant: Histopathologic Features of the Gastrointestinal Tract and Report of a Novel AP1S1 Variant

Inherited syndromes of congenital enteropathy are rare, with many genetic causes described. Mutations of the AP1S1 gene results in the syndrome of intellectual disability, enteropathy, deafness, peripheral neuropathy, ichthyosis, and keratoderma (IDEDNIK, formerly in the medical literature as MEDNIK). The clinicopathologic features of the enteropathy in IDEDNIK syndrome have not been fully explored. We describe a female infant who presented with metabolic acidosis, lethargy, and 14 watery stools per day. In the intensive care unit she required parenteral nutrition. She was found to have a novel homozygous pathogenic variant in the AP1S1 gene c.186T>G (p.Y62*). Esophagogastroduodenoscopy and colonoscopy at 6 months of age were grossly normal. However, histologic sections of the duodenum showed mild villous blunting and enterocytes with cytoplasmic vacuoles. CD10 immunostaining highlighted the disrupted brush border. MOC31 immunostaining was wild-type with a membranous pattern of expression. Electron microscopy of the duodenum showed scattered enterocytes cells with shortened and disrupted apical microvilli. Although there is a mixed gap diarrhea and disrupted brush border, there are no significant inclusions typical of microvillus inclusion disease, nor tufted enterocytes typical of tufting enteropathy, making the clinical and histopathologic features for this syndrome unique.

Abstract 1509: Longitudinal profiling of high-risk pediatric malignancies using a multiomics approach

For many pediatric cancer patients, commonly used gene-panel sequencing tests yield few actionable results, partly due to the complex genomic alterations present. We hypothesized that an unbiased approach, combining whole-genome (WGS) and RNA sequencing (RNAseq), could overcome this and lead to a more comprehensive understanding of these diseases. While prior studies have evaluated WGS and RNAseq in pediatric cancers, few focused primarily on metastatic or relapsed disease. We also placed special focus on longitudinal profiling of patients, including with additional deep sequencing, to capture tumor evolution at the primary and metastatic sites, and to quantify the utility of resampling.

We assembled a cohort of 191 high-risk pediatric oncology patients, including solid tumors, CNS tumors, and leukemias/lymphomas. We have representation of patients with relapsed/refractory disease (68), metastatic disease at diagnosis (10), rare diagnoses (19), prior cancer history, and estimated overall survival &lt;50%. We characterized 280 samples with WGS (tumor ~60X; germline ~30X) and/or RNAseq (tumor, polyA selected, ≥20 million reads), including multiple samples taken from 85 patients at different time points (diagnosis, resection, relapse, etc.). Variants (SNVs), structural rearrangements (SVs), mutational signatures, and copy-number alterations (CNAs) were identified using WGS. RNAseq was used to profile gene expression outliers, gene fusions, and expression of variants identified by WGS. The integrated results were used to prioritize potentially actionable variants for each patient. For 20 patients (44 samples), we performed targeted deep sequencing of the DNA (~500X) to profile tumor evolution that cannot be captured by WGS.

Multiple sampling from the same patient identified drastic spatial and temporal differences in the genomes and transcriptomes of these tumors. Using the Jaccard index as a measure of concordance between samples shows dynamic changes between samples collected at different time points across multiple modalities (range 0-1, 1 is identical); SNVs ranged from 0.01-0.79, SVs 0.01-0.73, major CNAs 0.07-0.99, minor CNAs 0.38-0.99, up expression outliers 0.12-0.56, down expression outliers 0.04-0.54, and fusions 0-1. Potentially biologically significant differences in therapy-induced mutations by platinum agents were also observed, highlighting the impact of therapy on tumor evolution. Clonal architectures were extracted from deep resequencing and show extensive spatial, temporal, and metastatic heterogeneity in these rare and highly aggressive malignancies that is not captured by WGS alone. Identifying clinically relevant evolution remains a challenge in most patients, but our results suggest that resampling of pediatric tumors at relapse or metastasis will be important for the effectiveness of targeted therapies in the future.

Citation Format: Henry J. Martell, Avanthi T. Shah, Alex G. Lee, Bogdan Tanasa, Stanley G. Leung, Aviv Spillinger, Heng-Yi Liu, Inge Behroozfard, Phuong Dinh, María V. Pons Ventura, Florette K. Hazard, Arun Rangaswami, Sheri L. Spunt, Norman J. Lacayo, Tabitha Cooney, Jennifer G. Michlitsch, Anurag K. Agrawal, Marcus R. Breese, Alejandro Sweet-Cordero. Longitudinal profiling of high-risk pediatric malignancies using a multiomics approach [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1509.

Juvenile granulosa cell tumor associated with Ollier disease

Prior case reports have described synchronous ovarian juvenile granulosa cell tumor (JGCT) and enchondromatosis in patients with Ollier disease and Maffucci syndrome. We present a case of a juvenile granulosa cell tumor with an IDH1 somatic mutation identified in the ovarian tissue in a 15-year-old female who presented with abnormal vaginal bleeding, several months of irregular menses, and a large multicystic adnexal mass. Multiple mixed lytic and sclerotic lesions were identified in the bones of the pelvis on imaging studies obtained during the work-up of her abdominal mass. Like previous reports in patients with undiagnosed enchondromatosis, these lesions were presumed to represent skeletal metastases; however, biopsy tissue revealed a hyaline cartilage neoplasm. Subspecialty review of the imaging findings revealed imaging features classic for Ollier disease involving the flat bones of the pelvis. It is important for radiologists to be familiar with the association between enchondromatosis and JGCT. When a female patient with enchondromatosis presents with a large, unilateral, mixed solid-cystic ovarian mass, the diagnosis of JGCT can be suggested. Alternatively, when a patient is diagnosed with JGCT, any skeletal lesions should be scrutinized for imaging features that suggest a hyaline cartilage neoplasm to avoid the misdiagnosis of skeletal metastases in a patient with previously undiagnosed Ollier disease or Maffucci syndrome. To our knowledge, this is the second reported confirmed case of an IDH1 somatic mutation identified in the ovarian tissue of a JGCT in a patient with Ollier disease.

Development and characterization of new patient-derived xenograft (PDX) models of osteosarcoma with distinct metastatic capacities

Models to study metastatic disease in rare cancers are needed to advance preclinical therapeutics and to gain insight into disease biology, especially for highly aggressive cancers with a propensity for metastatic spread. Osteosarcoma is a rare cancer with a complex genomic landscape in which outcomes for patients with metastatic disease are poor. As osteosarcoma genomes are highly heterogeneous, a large panel of models is needed to fully elucidate key aspects of disease biology and to recapitulate clinically-relevant phenotypes. We describe the development and characterization of osteosarcoma patient-derived xenografts (PDXs) and a panel of PDX-derived cell lines. Matched patient samples, PDXs, and PDX-derived cell lines were comprehensively evaluated using whole genome sequencing and RNA sequencing. PDXs and PDX-derived cell lines largely maintained the expression profiles of the patient from which they were derived despite the emergence of whole-genome duplication (WGD) in a subset of cell lines. These cell line models were heterogeneous in their metastatic capacity and their tissue tropism as observed in both intravenous and orthotopic models. As proof-of-concept study, we used one of these models to test the preclinical effectiveness of a CDK inhibitor on the growth of metastatic tumors in an orthotopic amputation model. Single-agent dinaciclib was effective at dramatically reducing the metastatic burden in this model.

Utility of frozen section in pediatric and adolescent malignant ovarian nonseminomatous germ cell tumors: A report from the children's oncology group

PURPOSE

In adult women, most malignant ovarian tumors are epithelial in origin. The use of intra-operative frozen section to distinguish between benign and malignant histology is reliable in guiding operative decision-making to determine the extent of surgical staging required. Pediatric and adolescent patients with ovarian masses have a much different spectrum of pathology with most tumors arising from germ cell precursors. This review was undertaken to assess the concordance between the intra-operative frozen section and the final diagnosis as an aid to guide extent of surgical staging in a group of pediatric and adolescent patients with malignant ovarian germ cell tumors.

METHODS

Records of patients aged 0 to 20 years with malignant ovarian germ cell tumors enrolled on Children's Oncology Group study AGCT0132 were reviewed. Pathology reports from patients who had both intra-operative frozen section diagnosis and final paraffin section diagnosis were compared using descriptive statistics. By inclusion criteria for the study, all patients had a final diagnosis of malignancy with required yolk sac tumor, choriocarcinoma or embryonal carcinoma histology. Available central review of pathology final paraffin section slides were compared with final institution pathology reports.

RESULTS

Of 131 eligible patients with ovarian germ cell tumors, 60 (45.8%) had both intra-operative frozen section and final paraffin section diagnoses available. Intra-operative frozen section diagnoses were classified as: incorrect diagnosis of benign tumor (13.3%), confirmation of malignancy (61.7%), immature teratoma (16.7%), germ cell tumor not otherwise specified (5%) and no diagnosis provided (3.3%). Intra-operative frozen section was incorrect in 23 of 60 (38.3%) patients evaluated. Central pathology review was concordant with the final institution pathology diagnosis in 76.3% of patients. Central pathology review identified additional germ cell tumor components in 23.7% of patients.

CONCLUSIONS

In pediatric and adolescent patients with a confirmed final diagnosis of ovarian germ cell malignancy, intra-operative frozen section diagnosis is not reliable to inform the extent of surgical staging required. Central review by an expert germ cell tumor pathologist provides important additional information to guide therapy.

Abstract 54: Integrative analysis of whole-genome and RNA sequencing in high-risk pediatric malignancies

The use of sequencing-based assays for clinical management of pediatric cancer patients has become increasingly common. However, for many pediatric patients, gene panel based sequencing tests yield few actionable results. Given the complex genomic alterations present in many pediatric cancers, especially high-risk solid tumors, we hypothesized that an unbiased approach might reveal more actionable findings and lead to a more comprehensive understanding of these diseases. To accomplish this, we integrated whole-genome sequencing (WGS) with RNAseq in the analysis of a pediatric oncology cohort, with a focus on longitudinal cases to capture potential tumor evolution in metastatic or treated cases.

Our cohort consists of 269 high-risk pediatric oncology patients, including patients with relapsed/refractory disease, metastatic disease at diagnosis, prior cancer history, a rare diagnosis, or an estimated overall survival &lt;50%. Solid tumors, CNS tumors, and leukemia/lymphomas are all represented. In total, 391 samples were characterized using WGS (tumor ~60X; germline ~30X) and/or RNAseq (tumor, polyA selected, ≥20 million reads). For 85 of these patients, multiple samples were collected at different time points (diagnosis, resection, relapse, etc.) to identify changes in the cancer over time. If panel testing was performed as part of their clinical care, a comparison to the integrated WGS/RNA analysis was made. WGS was used to identify variants (SNVs), structural rearrangements (SVs), mutational signatures, and copy-number alterations (CNAs). RNAseq was used to identify gene expression outliers, gene fusions, and confirm the expression of variants identified using WGS. The combination of WGS and RNAseq was then used to identify and prioritize potentially actionable variants for each patient.

Our results show that the integration of WGS and RNAseq can provide more and higher-quality actionable information than either modality alone, whilst also capturing the majority of actionable variants detected by panel sequencing. RNAseq identified not only druggable fusions and expression outliers, but also many rare and novel fusions. WGS provided fusion validation but highlighted the limitations of WGS alone in identifying fusions resulting from complex SVs. Conversely, WGS was adept at capturing genome-wide patterns of CNAs and loss of heterozygosity that are missed by gene-centric panels. Further RNAseq integration enabled prioritization of expressed SNVs as well as CNAs and SVs that significantly alter gene expression. We also used WGS to extract mutational signatures and tracked their evolution across longitudinal samples. We found potentially biologically significant differences in therapy-induced mutations caused by platinum and alkylating agents. Our unbiased approach has enabled further discovery that advances our understanding of these rare and highly aggressive malignancies.

Citation Format: Henry J. Martell, Avanthi Tayi Shah, Alex G. Lee, Bogdan Tanasa, Stanley G. Leung, Aviv Spillinger, Heng-Yi Liu, Inge Behroozfard, Phuong Dinh, Maria V. Pons Ventura, Florette K. Hazard, Arun Rangaswami, Sheri L. Spunt, Norman J. Lacayo, Tabitha Cooney, Jennifer G. Michlitsch, Anurag K. Agrawal, Marcus R. Breese, E. Alejandro Sweet-Cordero. Integrative analysis of whole-genome and RNA sequencing in high-risk pediatric malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 54.

The Use of Fluorescence in situ Hybridization to Confirm PRKACA Gene Rearrangement in Fibrolamellar Hepatocellular Carcinoma: A Validation Study

OBJECTIVE

The objectives of this study are to define the specificity of the DNAJB1-PRKACA fusion transcript for the fibrolamellar subtype of hepatocellular carcinoma (FL-HCC) by testing a targeted sampling of other hepatic neoplasms/proliferations and extrahepatic neoplasms seen in children and young adults and to develop a FISH assay using a commercially available PRKACA break apart probe for use in a CLIA-certified clinical laboratory.

METHODS

Formalin fixed paraffin embedded tissue sections from 12 FL-HCC cases, 142 cases of other hepatic neoplasms/proliferations (conventional HCC, focal nodular hyperplasia (FNH), hepatocellular adenoma (HA) and hepatoblastoma (HB)) and extrahepatic neoplasms (neuroblastoma (NB), Wilms tumor (WT) and Gastrointestinal neuroendocrine tumor (GNET)) and 60 matched background normal control tissues underwent fluorescence in situ hybridization (FISH) testing using a break apart probe targeting the PRKACA gene locus on chromosome 19 using standard techniques.

RESULTS

The PRKACA gene rearrangement was detected in 11/12 (92%) FL-HCC cases and 1/94 (1%) of conventional HCC cases. All other cases and background control tissues were negative for the PRKACA gene rearrangement. These findings establish a test sensitivity of 91.7% and specificity of 99.5%.

CONCLUSION

This study shows that, using standard techniques, FISH testing with a commercially available break apart probe targeting the PRKACA gene can be used as a surrogate for the DNAJB1-PRKACA fusion commonly found in FL-HCC. Also, the PRKACA gene rearrangement is not expressed in other hepatic neo-plasms/proliferations or extrahepatic neoplasms seen in children and young adults. Finally, FISH testing can be used as a diagnostic tool to confirm the diagnosis of FL-HCC, in the appropriate clinical setting.

Next-Generation Sequencing as an Auxiliary Tool in Pediatric Laryngeal Lymphoma Diagnosis

Lymphomatous involvement of the larynx is a rare entity. We present a case of atypical laryngotracheitis as the initial manifestation of non-Hodgkin's lymphoma in a pediatric patient. The diagnosis was aided through the use of microbial cell-free DNA (mcfDNA) testing, which detected the presence of Epstein-Barr virus in the patient's plasma. This enabled the consideration of an Epstein-Barr virus-related lymphoproliferative process, leading to additional workup and the final diagnosis of lymphoma. To our knowledge, this is the first case of mcfDNA testing leading not simply to an infectious organism, but further to a new oncologic diagnosis. Plasma mcfDNA testing has the potential to inform clinical practice beyond classic infectious disease manifestations. In this article, we review both the possible future applications and the areas of further investigation that remain.

A Comprehensive Circulating Tumor DNA Assay for Detection of Translocation and Copy-Number Changes in Pediatric Sarcomas

Most circulating tumor DNA (ctDNA) assays are designed to detect recurrent mutations. Pediatric sarcomas share few recurrent mutations but rather are characterized by translocations and copy-number changes. We applied Cancer Personalized Profiling by deep Sequencing (CAPP-Seq) for detection of translocations found in the most common pediatric sarcomas. We also applied ichorCNA to the combined off-target reads from our hybrid capture to simultaneously detect copy-number alterations (CNA). We analyzed 64 prospectively collected plasma samples from 17 patients with pediatric sarcoma. Translocations were detected in the pretreatment plasma of 13 patients and were confirmed by tumor sequencing in 12 patients. Two of these patients had evidence of complex chromosomal rearrangements in their ctDNA. We also detected copy-number changes in the pretreatment plasma of 7 patients. We found that ctDNA levels correlated with metastatic status and clinical response. Furthermore, we detected rising ctDNA levels before relapse was clinically apparent, demonstrating the high sensitivity of our assay. This assay can be utilized for simultaneous detection of translocations and CNAs in the plasma of patients with pediatric sarcoma. While we describe our experience in pediatric sarcomas, this approach can be applied to other tumors that are driven by structural variants.

Stage 4S Neuroblastoma: Molecular, Histologic, and Immunohistochemical Characteristics and Presence of 2 Distinct Patterns of MYCN Protein Overexpression-A Report From the Children's Oncology Group

Stage 4S neuroblastoma (4SNB) is associated with spontaneous tumor regression and an excellent prognosis. However, a small group of the patients have a poor prognosis. One hundred eighty-five stage 4SNB cases filed at the Children's Oncology Group Neuroblastoma Pathology Reference Laboratory were studied. MYCN oncogene status [non-amplified (NA) vs. Amplified (A)] determined by fluorescence in situ hybridization, MYC-family (MYCN/MYC) protein expression [no-overexpression(-)/(+/-) vs. overexpression(+)] by immunohistochemistry and histopathology by International Neuroblastoma Pathology Classification [Favorable Histology (FH) vs. Unfavorable Histology (UH)] with particular attention to nucleolar hypertrophy [NH(-) vs. (+)] were assessed with patient survival. One hundred forty-seven (79.5%) tumors were MYCN-NA, FH, MYC-family protein(-)/(+/-), and NH(-) with a good prognosis [88.5±3.1% 3-y event-free survival (EFS); 94.1±2.3% 3-y overall survival (OS)]. Among MYCN-NA tumors, 11 demonstrated MYCN protein(+) with a moderate and uniform (M/U) staining pattern: they were FH(10/11), NH(-), 1 showed MYC protein(+) simultaneously, and all patients are alive. Also found were 5 MYC protein(+) and MYCN(-)/(+/-) tumors; they were FH without NH (4/5), and all patients are alive. Among MYCN-A tumors, 18 had MYCN protein(+) with a strong and heterogeneous (S/H) staining pattern, 9 had UH (44.4±23.4% EFS/OS) and 9 had FH (68.6±19.2% EFS/OS), and 15 showed NH(+). Two tumors had MYCN protein(-)/(+/-) despite MYCN-A; both were FH and NH(-), and 1 patient died. S/H staining pattern of MYCN protein overexpression by immunohistochemistry was associated with MYCN amplification, NH(+) and a poor prognosis. In contrast, the M/U staining pattern was associated with MYCN nonamplification and NH(-), and had no adverse prognostic effects for the stage 4SNB patients.

Composite Neuroblastoma Metastatic to a Lymph Node: The Novel Histopathologic Diagnosis of a Unique Multiclonal Neoplasm

OBJECTIVE

Composite neuroblastoma is a tumor composed of multiple tumoral clones within the neuroblastoma family. To date, establishing this unique histopathologic diagnosis has required the evaluation of the primary tumor mass. We report a case of composite neuroblastoma diagnosed by evaluation of a metastatic lymph node.

METHODS

One abdominal lymph node involved by tumor was evaluated in a 6-year-old boy. The primary abdominal mass was not examined. Following histopathologic examination, clonality studies using comparative genomic hybridization (CGH) and fluorescence in situ hybridization (FISH) were also performed.

RESULTS

Two distinct tumor components were identified by histopathologic evaluation and classified as differentiating neuroblastoma (component A) and poorly differentiated neuroblastoma (component B). Based on the patient's age, each clone was further classified as Unfavorable Histology. The presence of these two different tumoral clones was confirmed by CGH and FISH.

CONCLUSION

This case affirms the histopathologic approach to evaluating composite tumors, as established by the International Neuroblastoma Pathology Classification (INPC) model for ganglioneuroblastoma, nodular tumors. Also, when both components are metastatic, this case demonstrates that composite tumors can be diagnosed by the evaluation of metastatic lesions alone. Finally, it supports the addition of composite neuroblastoma to a future version of the INPC.

Multimodality treatment including whole pleura radiation therapy for DICER1-associated pediatric pleuropulmonary blastoma

Limited data are available regarding radiation therapy in pediatric pleuropulmonary blastoma (PPB). We report the case of a 3-year-old girl with type II PPB successfully treated with trimodality therapy including multiagent chemotherapy, resection, and whole pleura radiation therapy. While longer follow-up is required to confirm ultimate local tumor control and long-term post-treatment sequelae, currently 3.5 years following therapy, she is well, without recurrent disease or observable toxicity. The goal of this report is to add our experience to the literature regarding PPB, its management, and treatment, as prospective randomized controlled trials are not feasible due to the rarity of this disease.

Three Infants with Pathogenic Variants in the ABCA3 Gene: Presentation, Treatment, and Clinical Course

ABCA3 deficiency is a rare cause of neonatal respiratory failure. Biallelic complete loss of function variants lead to neonatal demise without lung transplantation, but children with partial function variants have variable outcomes. The favorable clinical course of 3 such infants presenting with respiratory distress at birth is described.

Sclerosing Epithelioid Fibrosarcoma of the Kidney: First Reported Case in a Young Child

Sclerosing epithelioid fibrosarcoma (SEF) is a rare variant of fibrosarcoma primarily arising in the deep soft tissue of the extremities and trunk. Despite having the morphologic appearance of a low-grade sarcoma, it generally has an aggressive clinical course with frequent local recurrences and distant metastases. It typically occurs in middle aged adults and is characterized by immunoexpression of MUC4 and recurrent gene fusions, most commonly EWSR1-CREB3L1. We report a primary renal SEF in a 4-year-old male. To our knowledge, this is the youngest patient reported with SEF and the second case of SEF in a pre-adolescent child. It is the eleventh reported case of primary renal SEF in the literature. While SEF arising in visceral organs is rare, the kidney is the most common primary site of any visceral organ. This case demonstrates SEF can occur in pre-adolescents, is an important consideration when evaluating sarcomas in young children, and should be considered in the differential diagnosis for primary renal tumors.

ALK-positive compound Spitz nevus with extensive perineural and intraneural neurotropism

Historically recognized by their characteristic histopathologic features, Spitz neoplasms are now known to be molecularly defined by mutually exclusive recurrent abnormalities that cause activation of the MAPK pathway. Spitz neoplasms with ALK rearrangements frequently demonstrate polypoid growth with a plexiform arrangement of nested, fusiform melanocytes in intersecting fascicles. Although neurotropism has been described in indolent Spitz neoplasms, this feature is not frequently mentioned in publications on histopathologic assessment of this group of melanocytic tumors. Here, we present an unusual case of a 3-year-old female with an ALK-positive compound Spitz nevus with extensive perineural and intraneural neurotropism occurring on the vermilion border of the lower lip.

Abstract B20: Integrative analysis of whole-genome and RNA sequencing in high-risk pediatric malignancies

Targeted gene panel sequencing has become increasingly common in the management of pediatric cancer patients. For some patients, these cancer gene panel tests have identified clinically actionable findings, but for many pediatric patients, no actionable alterations are identified. This is in part due to the low mutational burden of pediatric malignancies; thus, an unbiased approach may shed light on potentially actionable findings. To accomplish this, we examined the feasibility and utility of whole-genome sequencing (WGS) and RNA sequencing (RNAseq) in the management of high-risk pediatric oncology patients. We describe our experience with a cohort of over 100 high-risk pediatric oncology patients, with a combination of solid tumors, brain tumors, and hematologic malignancies. The majority of patients were deemed high-risk due to relapsed/refractory disease. A second group of patients was defined as high-risk at time of initial diagnosis due to the presence of metastatic disease, an estimated overall survival of less than 50%, a rare tumor, an undifferentiated tumor, or prior history of another malignancy. When possible, multiple samples from an individual patient were collected (i.e., specimens at biopsy, resection, relapse, and/or from metastatic sites) to allow for evaluation of inter- and intratumoral heterogeneity. Close to 200 tumor samples were available for analysis using WGS and/or RNAseq analysis. Somatic DNA samples were sequenced to an average depth of 60X and germline samples to 30X. WGS samples were analyzed for SNVs, structural rearrangements (SVs), copy-number alterations (CNAs), and mutational signatures. RNAseq was performed to a depth of at least 20 million paired-end reads for each sample. These samples were analyzed to identify known and novel gene-fusions, measure allele specific expression of SNVs, and perform gene-expression outlier analysis. Expression of variants (SNV/SV) identified using WGS were confirmed using RNAseq. For gene expression outliers detected using RNAseq, the WGS data were used to predict possible mechanisms for the aberrant expression (such as CNA, gene fusions, or promoter hijacking). This analysis suggests that WGS and RNAseq analysis is feasible in a clinical setting and can reliably identify variants reported on gene panel tests. Furthermore, the use of WGS/RNAseq results in additional clinically informative findings while also enabling novel research to further advance our understanding of these rare and highly aggressive pediatric malignancies.

Citation Format: Avanthi T. Shah, Marcus R. Breese, Alex G. Lee, Henry J. Martell, Bogdan Tanasa, Stanley G. Leung, Aviv Spillingeer, Heng-Yi Liu, Inge Behroozfard, Phuong Dinh, Florette K. Hazard, Soo-Jin Cho, Arun Rangaswami, Norman J. Lacayo, Sheri L. Spunt, Tabitha Cooney, Jennifer G. Michlitsch, Anurag K. Agarwaal, Alejandro Sweet-Cordero. Integrative analysis of whole-genome and RNA sequencing in high-risk pediatric malignancies [abstract]. In: Proceedings of the AACR Special Conference on the Advances in Pediatric Cancer Research; 2019 Sep 17-20; Montreal, QC, Canada. Philadelphia (PA): AACR; Cancer Res 2020;80(14 Suppl):Abstract nr B20.

Impact of a deep learning assistant on the histopathologic classification of liver cancer

Artificial intelligence (AI) algorithms continue to rival human performance on a variety of clinical tasks, while their actual impact on human diagnosticians, when incorporated into clinical workflows, remains relatively unexplored. In this study, we developed a deep learning-based assistant to help pathologists differentiate between two subtypes of primary liver cancer, hepatocellular carcinoma and cholangiocarcinoma, on hematoxylin and eosin-stained whole-slide images (WSI), and evaluated its effect on the diagnostic performance of 11 pathologists with varying levels of expertise. Our model achieved accuracies of 0.885 on a validation set of 26 WSI, and 0.842 on an independent test set of 80 WSI. Although use of the assistant did not change the mean accuracy of the 11 pathologists (p = 0.184, OR = 1.281), it significantly improved the accuracy (p = 0.045, OR = 1.499) of a subset of nine pathologists who fell within well-defined experience levels (GI subspecialists, non-GI subspecialists, and trainees). In the assisted state, model accuracy significantly impacted the diagnostic decisions of all 11 pathologists. As expected, when the model's prediction was correct, assistance significantly improved accuracy (p = 0.000, OR = 4.289), whereas when the model's prediction was incorrect, assistance significantly decreased accuracy (p = 0.000, OR = 0.253), with both effects holding across all pathologist experience levels and case difficulty levels. Our results highlight the challenges of translating AI models into the clinical setting, and emphasize the importance of taking into account potential unintended negative consequences of model assistance when designing and testing medical AI-assistance tools.

Epigenetic Targeting of TERT-Associated Gene Expression Signature in Human Neuroblastoma with TERT Overexpression

Neuroblastoma is a deadly pediatric solid tumor with infrequent recurrent somatic mutations. Particularly, the pathophysiology of tumors without MYCN amplification remains poorly defined. Utilizing an unbiased approach, we performed gene set enrichment analysis of RNA-sequencing data from 498 patients with neuroblastoma and revealed a differentially overexpressed gene signature in MYCN nonamplified neuroblastomas with telomerase reverse transcriptase (TERT) gene overexpression and coordinated activation of oncogenic signaling pathways, including E2Fs, Wnt, Myc, and the DNA repair pathway. Promoter rearrangement of the TERT gene juxtaposes the coding sequence to strong enhancer elements, leading to TERT overexpression and poor prognosis in neuroblastoma, but TERT-associated oncogenic signaling remains unclear. ChIP-seq analysis of the human CLB-GA neuroblastoma cells harboring TERT rearrangement uncovered genome-wide chromatin co-occupancy of Brd4 and H3K27Ac and robust enrichment of H3K36me3 in TERT and multiple TERT-associated genes. Brd4 and cyclin-dependent kinases (CDK) had critical regulatory roles in the expression and chromatin activation of TERT and multiple TERT-associated genes. Epigenetically targeting Brd4 or CDKs with their respective inhibitors suppressed the expression of TERT and multiple TERT-associated genes in neuroblastoma with TERT overexpression or MYCN amplification. ChIP-seq and ChIP-qPCR provided evidence that the CDK inhibitor directly inhibited Brd4 recruitment to activate chromatin globally. Therefore, inhibiting Brd4 and CDK concurrently with AZD5153 and dinaciclib would be most effective in tumor growth suppression, which we demonstrated in neuroblastoma cell lines, primary human cells, and xenografts. In summary, we describe a unique mechanism in neuroblastoma with TERT overexpression and an epigenetically targeted novel therapeutic strategy. SIGNIFICANCE: Epigenetically cotargeting Brd4 and Cdks suppresses human neuroblastoma with TERT overexpression by inhibiting the TERT-associated gene expression networks.

Obstetric and neonatal outcomes in pregnancies complicated by fetal lung masses: does final histology matter?. J Matern Fetal Neonatal Med 2019;34:3662-3668. [PMID: 31722592 DOI: 10.1080/14767058.2019.1689559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Purpose: Fetal lung masses complicate approximately 1 in 2000 live births. Our aim was to determine whether obstetric and neonatal outcomes differ by final fetal lung mass histology.Materials and methods: A review of all pregnancies complicated by a prenatally diagnosed fetal lung mass between 2009 and 2017 at a single academic center was conducted. All cases included in the final analysis underwent surgical resection and histology diagnosis was determined by a trained pathologist. Clinical data were obtained from review of stored electronic medical records which contained linked maternal and neonatal records. Imaging records included both prenatal ultrasound and magnetic resonance imaging. Fisher's exact test was used for categorical variables and the Kruskal-Wallis test was used for continuous variables. The level of significance was p<.05.Results: Of 61 pregnancies complicated by fetal lung mass during the study period, 45 cases underwent both prenatal care and postnatal resection. Final histology revealed 10 cases of congenital pulmonary airway malformation (CPAM) type 1, nine cases of CPAM type 2, and 16 cases of bronchopulmonary sequestration. There was no difference in initial, maximal, or final CPAM volume ratio between groups, with median final CPAM volume ratio of 0.6 for CPAM type 1, 0.7 for CPAM type 2, and 0.3 for bronchopulmonary sequestration (p = .12). There were no differences in any of the maternal or obstetric outcomes including gestational age at delivery and mode of delivery between the groups. The primary outcome of neonatal respiratory distress was not statistically different between groups (p = .66). Median neonatal length of stay following delivery ranged from 3 to 4 days, and time to postnatal resection was similar as well, with a median of 126 days for CPAM type 1, 122 days for CPAM type 2, and 132 days for bronchopulmonary sequestration (p = .76).Conclusions: In our cohort, there was no significant association between histologic lung mass subtypes and any obstetric or neonatal morbidity including respiratory distress.

Delayed appearance of mature ganglia in an infant with an atypical presentation of total colonic and small bowel aganglionosis: a case report

Background

Total colonic and small bowel aganglionosis (TCSA) occurs in less than 1% of all Hirschsprung’s disease patients. Currently, the mainstay of treatment is surgery. However, in patients with TCSA, functional outcomes are often poor. A characteristic transition zone in TCSA can be difficult to identify which may complicate surgery and may often require multiple operations.

Case presentation

We present the case of a male infant who was diagnosed with biopsy-proven total colonic aganglionosis with extensive small bowel involvement as a neonate. The patient was diverted at one month of age based on leveling biopsies at 10 cm from the Ligament of Treitz. At 7 months of age, during stoma revision for a prolapsed stoma, intra-operative peristalsis was observed in nearly the entire length of the previously aganglionic bowel, and subsequent biopsies demonstrated the appearance of mature ganglion cells in a previously aganglionic segment.

Conclusions

TCSA remains a major challenge for pediatric surgeons. Our case introduces new controversy to our understanding of aganglionosis. Our observations warrant further research into the possibility of post-natal ganglion maturation and encourage surgeons to consider a more conservative surgical approach.

Abstract B25: Integrative analysis of whole-genome and RNA sequencing in high-risk pediatric malignancies

Clinical use of gene-panel based tumor sequencing has expanded exponentially over the past few years. While in some cases this molecular testing identifies clinically actionable findings, these highly targeted approaches may miss unanticipated, clinically meaningful or novel alterations. In cancers with poorly understood etiologies, including many pediatric solid or high-risk tumors, an unbiased approach may prove more useful. We sought to explore the feasibility and utility of whole-genome sequencing (WGS) and RNA sequencing (RNA-seq) in comparison to commercially available targeted gene-panel testing in pediatric oncology.

Herein we describe our experience with an initial cohort of 58 high-risk pediatric oncology patients (37 solid tumors, 11 brain tumors, and 10 leukemia/lymphomas). The majority of patients (n=40) had relapsed/refractory disease. An additional eighteen patients were defined as high-risk at time of initial diagnosis due to metastatic disease, a rare tumor, prior history of another cancer type, an undifferentiated tumor, or less than 50% survival. A total of 102 samples were obtained from these 58 patients, with 70 samples originating at the primary sites of disease and 32 samples from metastatic sites. Thirty-one samples were chemotherapy/radiation therapy naïve. A combination of WGS and RNA-seq were used to characterize available samples and compared to results from panel testing for that patient (performed as part of their clinical evaluation). Where possible, fresh frozen tissue (FFT) samples were obtained during clinically indicated surgical procedures. When FFT was unavailable, formalin-fixed, paraffin-embedded (FFPE) samples were used. When possible, multiple samples from an individual patient were collected (i.e., specimens obtained at biopsy, resection, relapse, and/or from metastatic sites). Germline DNA was isolated from peripheral blood, with the exception of leukemia patients where saliva was used. Somatic DNA samples were sequenced to an average depth of at least 60X and germline samples to at least 30X. Somatic RNA-seq was performed to a depth of at least 20 million paired-end reads for each sample. In-house as well as published tools and algorithms were used to analyze DNA samples for single-nucleotide variants (SNVs), structural rearrangements, and copy-number alterations. RNA samples were analyzed to identify known and novel gene fusions, to measure allele specific expression of SNVs, and to perform gene-expression outlier analysis.

Consistent with previous observations, the mutational burden across pediatric cancers was low. While common mutations were identified, there was a long tail of mutations that occurred at a low frequency. As anticipated, samples obtained post-chemotherapy had a higher mutational burden than treatment-naïve samples. TP53 was the most commonly mutated gene, but we also identified SNVs in other genes commonly mutated in cancer, such as ASXL1, NOTCH2, and RB1. Other novel recurring variants were discovered, further analysis of which is ongoing. Canonical gene fusions were detected in 8/8 patients as well as potentially novel fusions, confirmation of which is also ongoing. In nearly all patients, variants identified by gene panels were also identified through WGS/RNA-seq analysis; however, in 2 instances, variants reported by gene panel testing were reclassified as germline using our tumor/normal WGS analysis. These results indicate that integrated WGS and RNA-seq analysis is feasible in the clinical setting and can reliably identify variants reported on commercially available gene panel testing. However, this approach also resulted in additional clinically relevant findings and allows for novel discovery that will further advance our understanding of these rare and highly aggressive pediatric malignancies.

Citation Format: Marcus R. Breese, Avanthi T. Shah, Bogdan Tanasa, Alex G. Lee, Stanley G. Leung, Aviv Spillinger, Heng-Yi Liu, Florette K. Hazard, Alejandro Sweet-Cordero. Integrative analysis of whole-genome and RNA sequencing in high-risk pediatric malignancies [abstract]. In: Proceedings of the AACR Special Conference: Pediatric Cancer Research: From Basic Science to the Clinic; 2017 Dec 3-6; Atlanta, Georgia. Philadelphia (PA): AACR; Cancer Res 2018;78(19 Suppl):Abstract nr B25.

Genome-Informed Targeted Therapy for Osteosarcoma

Osteosarcoma is a highly aggressive cancer for which treatment has remained essentially unchanged for more than 30 years. Osteosarcoma is characterized by widespread and recurrent somatic copy-number alterations (SCNA) and structural rearrangements. In contrast, few recurrent point mutations in protein-coding genes have been identified, suggesting that genes within SCNAs are key oncogenic drivers in this disease. SCNAs and structural rearrangements are highly heterogeneous across osteosarcoma cases, suggesting the need for a genome-informed approach to targeted therapy. To identify patient-specific candidate drivers, we used a simple heuristic based on degree and rank order of copy-number amplification (identified by whole-genome sequencing) and changes in gene expression as identified by RNA sequencing. Using patient-derived tumor xenografts, we demonstrate that targeting of patient-specific SCNAs leads to significant decrease in tumor burden, providing a road map for genome-informed treatment of osteosarcoma. SIGNIFICANCE: Osteosarcoma is treated with a chemotherapy regimen established 30 years ago. Although osteosarcoma is genomically complex, we hypothesized that tumor-specific dependencies could be identified within SCNAs. Using patient-derived tumor xenografts, we found a high degree of response for "genome-matched" therapies, demonstrating the utility of a targeted genome-informed approach.This article is highlighted in the In This Issue feature, p. 1.

OncoKids: A Comprehensive Next-Generation Sequencing Panel for Pediatric Malignancies

The OncoKids panel is an amplification-based next-generation sequencing assay designed to detect diagnostic, prognostic, and therapeutic markers across the spectrum of pediatric malignancies, including leukemias, sarcomas, brain tumors, and embryonal tumors. This panel uses low input amounts of DNA (20 ng) and RNA (20 ng) and is compatible with formalin-fixed, paraffin-embedded and frozen tissue, bone marrow, and peripheral blood. The DNA content of this panel covers the full coding regions of 44 cancer predisposition loci, tumor suppressor genes, and oncogenes; hotspots for mutations in 82 genes; and amplification events in 24 genes. The RNA content includes 1421 targeted gene fusions. We describe the validation of this panel by using a large cohort of 192 unique clinical samples that included a wide range of tumor types and alterations. Robust performance was observed for analytical sensitivity, reproducibility, and limit of detection studies. The results from this study support the use of OncoKids for routine clinical testing of a wide variety of pediatric malignancies.

Magnetic Resonance Imaging of Tumor-Associated Macrophages: Clinical Translation

Purpose: Tumor-associated macrophages (TAMs) in malignant tumors have been linked to tumor aggressiveness and represent a new target for cancer immunotherapy. As new TAM-targeted immunotherapies are entering clinical trials, it is important to detect and quantify TAM with noninvasive imaging techniques. The purpose of this study was to determine if ferumoxytol-enhanced MRI can detect TAM in lymphomas and bone sarcomas of pediatric patients and young adults.Experimental Design: In a first-in-patient, Institutional Review Board-approved prospective clinical trial, 25 pediatric and young adult patients with lymphoma or bone sarcoma underwent ferumoxytol-enhanced MRI. To confirm ferumoxytol enhancement, five pilot patients (two lymphoma and three bone sarcoma) underwent pre- and postcontrast MRI. Subsequently, 20 patients (10 lymphoma and 10 bone sarcoma) underwent ferumoxytol-enhanced MRI 24 to 48 hours after i.v. injection, followed by tumor biopsy/resection and macrophage staining. To determine if ferumoxytol-MRI can differentiate tumors with different TAM content, we compared T2* relaxation times of lymphomas and bone sarcomas. Tumor T2* values of 20 patients were correlated with CD68⁺ and CD163⁺ TAM quantities on histopathology.Results: Significant ferumoxytol tumor enhancement was noted on postcontrast scans compared with precontrast scans (P = 0.036). Bone sarcomas and lymphomas demonstrated significantly different MRI enhancement and TAM density (P < 0.05). Within each tumor group, T2* signal enhancement on MR images correlated significantly with the density of CD68⁺ and CD163⁺ TAM (P < 0.05).Conclusions: Ferumoxytol-enhanced MRI is immediately clinically applicable and could be used to stratify patients with TAM-rich tumors to immune-targeted therapies and to monitor tumor response to these therapies. Clin Cancer Res; 24(17); 4110-8. ©2018 AACR.

CD47 is not Over-Expressed in Fibrolamellar Hepatocellular Carcinoma

OBJECTIVES

CD47 is a transmembrane receptor that inhibits phagocytosis. Over-expression of CD47 is associated with an increased risk of tumor growth and metastasis. Clinical trials based on anti-CD47 therapy in adults are underway in a variety of malignancies. CD47 has been shown to be over-expressed in conventional hepatocellular carcinoma (HCC), a common liver tumor in adults. To our knowledge, there have been no studies to evaluate CD47 expression in the fibrolamellar subtype of HCC (FL-HCC), common in children and young adults. This study will evaluate CD47 expression in FL-HCC and shed light on its suitability for anti-CD47 therapy.

METHODS

Using immunohistochemistry, 10 samples of FL-HCC from 8 patients were evaluated for CD47 (anti-phagocytic) and calreticulin (pro-phagocytic) expression. By direct comparison, CD47 and calreticulin expression were evaluated in 21 samples of conventional HCC. Additionally, transcriptome sequencing to detect CD47 mRNA expression was performed on fresh tissue from 1 FL-HCC institutional patient and previously published sequencing data from 20 additional samples was reviewed.

RESULTS

Immunohistochemistry showed only weak CD47 expression in 20% of FL-HCC samples. In contrast, 57% of conventional HCC samples showed CD47 expression. All (100%) FL-HCC samples showed moderate or strong calreticulin expression. The difference between CD47 and calreticulin expression in FL-HCC is statistically significant (p=0.0007). Transcriptome sequencing revealed no difference in CD47 expression between FL-HCC and normal liver samples.

CONCLUSIONS

CD47 is not over-expressed in FL-HCC. Our studies provide no support for expanding ongoing clinical trials in adults to include children and young adults with FL-HCC.

Synchronous Hepatoblastoma, Neuroblastoma, and Cutaneous Capillary Hemangiomas: A Case Report

Multiple synchronous tumors presenting in infancy raise concern for inherited or sporadic cancer predisposition syndromes, which include Beckwith-Wiedemann syndrome, familial adenomatous polyposis syndrome, and Li-Fraumeni syndrome. We report a case of a 7-month-old previously healthy male born following an in vitro fertilization-assisted twin pregnancy who presented with new-onset refractory shock, severe acidosis, and rapid decline over several hours. An autopsy revealed a ruptured liver involved by hepatoblastoma, an adrenal gland involved by neuroblastoma, and multiple cutaneous capillary hemangiomas. Standard genetic testing demonstrated that both twins were Gaucher disease (GD) carriers without evidence of other known cancer predisposition syndromes. This report describes a unique association of multiple synchronous tumors, which underscores the utility and importance of the pediatric autopsy. Moreover, given that the reported child was a GD carrier, the possibility the tumors were the result of a GD-mediated cancer-associated phenotype or an unrecognized sporadic clinical syndrome remains an unanswered, but intriguing, question worthy of further investigation.

Pregnancy outcomes in women with chronic endometritis and recurrent pregnancy loss

OBJECTIVE

To evaluate the prevalence of chronic endometritis (CE) in women with recurrent pregnancy loss (RPL) and compare pregnancy outcomes in women with and without CE.

DESIGN

Case-control observational study.

SETTING

Academic fertility practice.

PATIENT(S)

Women with two or more pregnancy losses.

INTERVENTION(S)

Hematoxylin and eosin (H & E) staining was performed on all endometrial biopsies and plasma cells were identified by morphology. Immunohistochemical (IHC) staining for CD138 was later applied to all tissue samples. Charts were reviewed to evaluate the outcome of the next clinical intrauterine pregnancy.

MAIN OUTCOME MEASURE(S)

Miscarriage rate and live birth rate.

RESULT(S)

A total of 107 women met inclusion criteria. The use of CD138 IHC staining resulted in a significantly higher prevalence of CE compared with the use of H & E staining and morphological assessment alone (56% [60/107] vs. 13% [14/107]). The 51 women with untreated CE were compared with the 45 women without CE by CD138 staining. Among those women with a subsequent pregnancy, the live birth rate in the next clinical intrauterine pregnancy after endometrial evaluation was 67.6% (23/34) in women with untreated CE and 87.1% (27/31) in women without CE. Age, body mass index (BMI), results of RPL evaluation, and number of prior losses were not significantly different between the two groups.

CONCLUSION(S)

CD138 IHC staining of endometrial biopsies in women with RPL provides increased sensitivity when screening for CE compared with H & E staining and morphological assessment alone. Untreated CE may contribute to poor pregnancy outcomes and deserves further investigation in a larger cohort.

Congenital peribronchial myofibroblastic tumor: case report of an asymptomatic infant with a rapidly enlarging pulmonary mass and review of the literature

BACKGROUND

Congenital peribronchial myofibroblastic tumor (CPMT) is a rare, benign lung tumor of infants, with only 19 reported cases worldwide. It is often diagnosed by prenatal imaging or in the immediate postnatal period due to co-morbidities like polyhydramnios, fetal hydrops, respiratory distress, and heart failure.

OBSERVATION

We report the oldest known infant (8 weeks old) diagnosed with CPMT, and present his clinical course including the relevant radiographic and histopathologic findings.

CONCLUSIONS

CPMT is a rare tumor that should be considered among other primary lung tumors of infancy (developmental, benign, and malignant) even if not detected prenatally or in the immediate postnatal period.

Genomic analysis of fibrolamellar hepatocellular carcinoma

Pediatric tumors are relatively infrequent, but are often associated with significant lethality and lifelong morbidity. A major goal of pediatric cancer research has been to identify key drivers of tumorigenesis to eventually develop targeted therapies to enhance cure rate and minimize acute and long-term toxic effects. Here, we used genomic approaches to identify biomarkers and candidate drivers for fibrolamellar hepatocellular carcinoma (FL-HCC), a very rare subtype of pediatric liver cancer for which limited therapeutic options exist. In-depth genomic analyses of one tumor followed by immunohistochemistry validation on seven other tumors showed expression of neuroendocrine markers in FL-HCC. DNA and RNA sequencing data further showed that common cancer pathways are not visibly altered in FL-HCC but identified two novel structural variants, both resulting in fusion transcripts. The first, a 400 kb deletion, results in a DNAJB1-PRKCA fusion transcript, which leads to increased cAMP-dependent protein kinase (PKA) activity in the index tumor case and other FL-HCC cases compared with normal liver. This PKA fusion protein is oncogenic in HCC cells. The second gene fusion event, a translocation between the CLPTM1L and GLIS3 genes, generates a transcript whose product also promotes cancer phenotypes in HCC cell lines. These experiments further highlight the tumorigenic role of gene fusions in the etiology of pediatric solid tumors and identify both candidate biomarkers and possible therapeutic targets for this lethal pediatric disease.

Development of novel tumor-targeted theranostic nanoparticles activated by membrane-type matrix metalloproteinases for combined cancer magnetic resonance imaging and therapy

A major drawback with current cancer therapy is the prevalence of unrequired dose-limiting toxicity to non-cancerous tissues and organs, which is further compounded by a limited ability to rapidly and easily monitor drug delivery, pharmacodynamics and therapeutic response. In this report, the design and characterization of novel multifunctional "theranostic" nanoparticles (TNPs) is described for enzyme-specific drug activation at tumor sites and simultaneous in vivo magnetic resonance imaging (MRI) of drug delivery. TNPs are synthesized by conjugation of FDA-approved iron oxide nanoparticles ferumoxytol to an MMP-activatable peptide conjugate of azademethylcolchicine (ICT), creating CLIO-ICTs (TNPs). Significant cell death is observed in TNP-treated MMP-14 positive MMTV-PyMT breast cancer cells in vitro, but not MMP-14 negative fibroblasts or cells treated with ferumoxytol alone. Intravenous administration of TNPs to MMTV-PyMT tumor-bearing mice and subsequent MRI demonstrates significant tumor selective accumulation of the TNP, an observation confirmed by histopathology. Treatment with CLIO-ICTs induces a significant antitumor effect and tumor necrosis, a response not observed with ferumoxytol. Furthermore, no toxicity or cell death is observed in normal tissues following treatment with CLIO-ICTs, ICT, or ferumoxytol. These findings demonstrate proof of concept for a new nanotemplate that integrates tumor specificity, drug delivery and in vivo imaging into a single TNP entity through attachment of enzyme-activated prodrugs onto magnetic nanoparticles. This novel approach holds the potential to significantly improve targeted cancer therapies, and ultimately enable personalized therapy regimens.

Liver pathology in infantile mitochondrial DNA depletion syndrome

Mitochondrial DNA (mtDNA) depletion syndrome is a relatively novel cause of hepatic dysfunction in the pediatric population. It is caused by mutations in either mtDNA or nuclear DNA (nDNA) that result in a quantitative reduction in mtDNA and, in turn, dysfunctional oxidative phosphorylation. In infants, it results in the hepatocerebral phenotype, characterized by hyperbilirubinemia, coagulopathy, lactic acidosis, hypoglycemia, lethargy, encephalopathy, developmental delay, and hypotonia. Three infants diagnosed with mtDNA depletion syndrome at The Children's Hospital of Philadelphia were identified, and their clinical presentation, disease course, and histologic and ultrastructural features of liver samples (pre- and postmortem) were characterized. While a different mutant gene was identified in each child, they all showed clinical evidence of metabolic dysfunction soon after birth and expired by 1 year of age. Steatosis, cholestasis, and cytoplasmic crowding by atypical mitochondria were consistent pathologic liver findings. Other findings included hepatocyte hypereosinophilia, fibrosis, and hemosiderosis. This analysis provides insight into the important clinical signs/symptoms and histopathologic and ultrastructural features of mtDNA depletion syndrome in infants and young children. Knowledge of these characteristics will facilitate early recognition and appropriate treatment of this rare disorder. Additionally, ultrastructural evaluation of liver samples by electron microscopy is an important diagnostic component of hepatic dysfunction caused by metabolic abnormalities. This type of analysis should be routinely employed in the setting of unexplained cholestasis, especially when accompanied by steatosis and hepatocyte hypereosinophilia.

Hemoglobin Hakkari: an autosomal dominant form of beta thalassemia with inclusion bodies arising from de novo mutation in exon 2 of beta globin gene

Certain beta globin gene mutations produce a thalassemia major phenotype in the heterozygous state. While most such patients have thalassemia intermedia, we describe a young Guatemalan child with a de novo mutation in the beta globin gene, codon 31 T --> G (Hemoglobin Hakkari), who developed severe anemia at the age of 10 months and remains transfusion-dependent. The substitution of B13 leucine with arginine in the beta globin results in alteration of a critical heme contact point resulting in an extremely unstable variant hemoglobin and a clinical picture that is characterized by ineffective erythropoiesis and numerous intracytoplasmic inclusions within the erythrocyte precursors of the bone marrow. .

Tissue microarrays from bone marrow aspirates for high-throughput assessment of immunohistologic markers in pediatric acute leukemia

Gene expression profiling studies have been employed to investigate prognostic subgroups in pediatric acute leukemia. Tissue microarrays (TMAs) are useful for high-throughput analysis of protein expression of target genes in acute leukemia samples and for validation of gene microarray analysis. Using cryopreserved samples of pediatric acute leukemia bone marrow aspirates, we constructed TMA from as few as 1 million cells. Bone marrow core biopsies from the same patients were included on the same TMA for comparison. A panel of 15 immunohistochemical markers typically used for diagnosis as well as those targeting recently characterized, prognostically relevant molecules of interest in pediatric acute leukemia was used to evaluate protein expression. Staining results confirm that suspension cells from bone marrow aspirates can be effectively used to derive protein expression data from multiple cases simultaneously with comparable efficacy to that of biopsy tissue. This method allows for new markers of diagnostic, prognostic, or therapeutic importance to be screened on large numbers of study patients. Furthermore, this technique may facilitate the inclusion of small samples, aspirates, and body fluids in large-scale studies of protein expression in clinical trials and protocols in which tissue biopsies are often unavailable.