18 F-FDG PET/CT in Pediatric ALK-Positive Histiocytosis With Isolated CNS Involvement.

ABSTRACT: An 11-year-old girl presented with focal impaired awareness seizures. MRI brain demonstrated a T2 hyperintense cortical lesion in the left temporal lobe with surrounding vasogenic edema. 18 F-FDG PET/CT was arranged to assess metabolic activity of the cerebral lesion, to screen the whole body for other metabolically active lesions, and to assist biopsy planning. The study demonstrated intensely increased FDG uptake within the left temporal lobe lesion without evidence of hypermetabolic lesions elsewhere on the whole-body acquisition. The brain lesion was excised, and histopathology and molecular testing were consistent with ALK-positive histiocytosis.

A Detailed Histologic and Molecular Assessment of the Diffuse Sclerosing Variant of Papillary Thyroid Carcinoma.

Diffuse sclerosing variant papillary thyroid carcinoma (DS-PTC) is characterized clinically by a predilection for children and young adults, bulky neck nodes, and pulmonary metastases. Previous studies have suggested infrequent BRAFV600E mutation but common RET gene rearrangements. Using strict criteria, we studied 43 DS-PTCs (1.9% of unselected PTCs in our unit). Seventy-nine percent harbored pathogenic gene rearrangements involving RET, NTRK3, NTRK1, ALK, or BRAF; with the remainder driven by BRAFV600E mutations. All 10 pediatric cases were all gene rearranged (P = .02). Compared with BRAFV600E-mutated tumors, gene rearrangement was characterized by psammoma bodies involving the entire lobe (P = .038), follicular predominant or mixed follicular architecture (P = .003), pulmonary metastases (24% vs none, P = .04), and absent classical, so-called "BRAF-like" atypia (P = .014). There was no correlation between the presence of gene rearrangement and recurrence-free survival. Features associated with persistent/recurrent disease included pediatric population (P = .030), gene-rearranged tumors (P = .020), microscopic extrathyroidal extension (P = .009), metastases at presentation (P = .007), and stage II disease (P = .015). We conclude that DS-PTC represents 1.9% of papillary thyroid carcinomas and that actionable gene rearrangements are extremely common in DS-PTC. DS-PTC can be divided into 2 distinct molecular subtypes and all BRAFV600E-negative tumors (1.5% of papillary thyroid carcinomas) are driven by potentially actionable oncogenic fusions.

Acthar Gel Inhibits the Activation of CD4+ and CD8+ T Cells.

Several inflammatory diseases are characterized by elevated T cell counts and high pro-inflammatory cytokine levels. Inhibiting T cell activity may reduce tissue damage associated with these diseases. Acthar® Gel has potent anti-inflammatory properties, yet little is known about its effect on T cells. This study compared the effects of Acthar, synthetic adrenocorticotropic hormone 1-24 (ACTH1-24) depot, and prednisolone in a murine model of T cell activation. Assessments of CD4+ helper and CD8+ cytotoxic T cells and plasma concentrations of interferon-γ (IFN-γ), interleukin-2 (IL-2), and tumor necrosis factor-α (TNF-α) were made following anti-CD3-activation. Acthar significantly reduced the number of activated CD4+ and CD8+ T cells at amounts comparable to synthetic ACTH1-24 depot or prednisolone. However, Acthar reduced production of IFN-γ, IL-2, and TNF-α significantly more than the other drugs, suggesting that the in vivo immunomodulatory effects of Acthar on T cells are distinct from synthetic ACTH1-24 depot or prednisolone.

Rare germline variants in childhood cancer patients suspected of genetic predisposition to cancer.

Identification of cancer-predisposing germline variants in childhood cancer patients is important for therapeutic decisions, disease surveillance and risk assessment for patients, and potentially, also for family members. We investigated the spectrum and prevalence of pathogenic germline variants in selected childhood cancer patients with features suggestive of genetic predisposition to cancer. Germline DNA was subjected to exome sequencing to filter variants in 1048 genes of interest including 176 known cancer predisposition genes (CPGs). An enrichment burden analysis compared rare deleterious germline CPG variants in the patient cohort with those in a healthy aged control population. A subset of predicted deleterious variants in novel candidate CPGs was investigated further by examining matched tumor samples, and the functional impact of AXIN1 variants was analyzed in cultured cells. Twenty-two pathogenic/likely pathogenic (P/LP) germline variants detected in 13 CPGs were identified in 19 of 76 patients (25.0%). Unclear association with the diagnosed cancer types was observed in 11 of 19 patients carrying P/LP CPG variants. The burden of rare deleterious germline variants in autosomal dominant CPGs was significantly higher in study patients versus healthy aged controls. A novel AXIN1 frameshift variant (Ser321fs) may impact the regulation of ß-catenin levels. Selection of childhood cancer patients for germline testing based on features suggestive of an underlying genetic predisposition could help to identify carriers of clinically relevant germline CPG variants, and streamline the integration of germline genomic testing in the pediatric oncology clinic.

Biopsy for molecular risk stratification in uveal melanoma: Yields and molecular characteristics in 119 patients.

BACKGROUND: Prognostic cytological and molecular features of uveal melanoma have been well researched and are essential in management. Samples can be obtained in vivo through fine needle aspirate biopsy, vitrector cutter, forceps or post-enucleation for off-site testing. This study aims to examine cytological and chromosome microarray yields of these samples. METHODS: A retrospective cohort analysis of 119 uveal melanoma biopsies submitted to our laboratory. Samples included those taken in vivo (n = 57) and post-enucleation (n = 62). Patient and tumour features were collected including age, sex, primary tumour location, basal diameter and tumour height. Prognostic outcomes measured include cell morphology, chromosomal status and immunohistochemistry. RESULTS: Post-enucleation biopsies accounted for just over half of our samples (52%). Post-enucleation samples had a more successful genetic yield than in vivo biopsies (77% vs. 50%, p = 0.04) though there was no difference for cytological yields. There was no difference in cytological or microarray yields between instruments. The vitrector biopsy group had the smallest tumour thickness (5 mm vs. 10 mm [fine-needle aspirate biopsy], p = 0.003). There was a strong correlation between monosomy 3, BAP1 aberrancy and epithelioid cell type in post-enucleation samples (Tb  = 0.742, p = 0.005). However, epithelioid morphology was not associated with either monosomy 3 (p = 0.07) or BAP1 aberrancy (p = 0.24) for in vivo biopsies. CONCLUSIONS: All three biopsy instruments provide similar cytological yields as post-enucleation sampling, although post-enucleation samples had a more successful chromosome microarray yield. Epithelioid cytomorphology alone is insufficient for prognostication in in vivo biopsies, immunohistochemistry would be a useful surrogate test.

Neuroblastoma Molecular Risk-Stratification of DNA Copy Number and ALK Genotyping via Cell-Free Circulating Tumor DNA Profiling.

BACKGROUND: MYCN amplification (MNA), segmental chromosomal aberrations (SCA) and ALK activating mutations are biomarkers for risk-group stratification and for targeted therapeutics for neuroblastoma, both of which are currently assessed on tissue biopsy. Increase in demand for tumor genetic testing for neuroblastoma diagnosis is posing a challenge to current practice, as the small size of the core needle biopsies obtained are required for multiple molecular tests. We evaluated the utility of detecting these biomarkers in the circulation. METHODS: Various pre-analytical conditions tested to optimize circulating-tumor DNA (ctDNA) copy number changes evaluations. Plasma samples from 10 patients diagnosed with neuroblastoma assessed for SCA and MNA using single nucleotide polymorphism (SNP) array approach currently used for neuroblastoma diagnosis, with MNA status assessed independently using digital-droplet PCR (ddPCR). Three patients (one in common with the previous 10) tested for ALK activating mutations p.F1174L and p.F1245I using ddPCR. RESULTS: Copy number detection is highly affected by physical perturbations of the blood sample (mimicking suboptimal sample shipment), which could be overcome using specialized preservative collection tubes. Pre-analytical DNA repair procedures on ctDNA before SNP chromosome microarray processing improved the lower limit of detection for SCA and MNA, defined as 20% and 10%, respectively. We detected SCA in 10/10 (100%) patients using SNP array, 7 of which also presented MNA. Circulating-free DNA (cfDNA) and matched tumor DNA profiles were generally identical. MNA was detected using ddPCR in 7/7 (100%) of MNA and 0/12 (0%) non-MNA cases. MNA and ALK mutation dynamic change was assessed in longitudinal samples from 4 and 3 patients (one patient with both), respectively, accurately reflected response to treatment in 6/6 (100%) and disease recurrence in 5/6 (83%) of cases. Samples taken prior to targeted treatment with the ALK inhibitor Lorlatinib and 6-8 weeks on treatment showed reduction/increase in ALK variants according to response to treatment. CONCLUSIONS: These results demonstrate the feasibility of ctDNA profiling for molecular risk-stratification, and treatment monitoring in a clinically relevant time frame and the potential to reduce fresh tissue requirements currently embedded in the management of neuroblastoma.

Chromosome microarray characterisation of chromosome arm 12p loss associated with complex molecular karyotype and recurrent adverse cytogenetic markers in multiple myeloma.

Copy number loss within chromosome 12 short arm (12p) has gained attention as an adverse cytogenetic marker in multiple myeloma. The prognostic significance and characterisation of the common minimal deleted region remains controversial between various studies with loss of CD27 proposed as the putative critical gene. We aimed to determine the frequency of 12p loss, its correlation with adverse cytogenetic markers further to define and characterise 12p deletions. Our study included a prospective cohort of 574 multiple myeloma patients referred for cytogenetic testing, including interphase fluorescence in situ hybridisation for IGH (14q32.33) translocations and chromosome microarray. Loss of 12p was detected in 54/574 (9.4%) patients and when compared with the non-12p loss group [520/574 (90.6%)], 12p loss patients demonstrated a statistically significant association with specific recurrent cytogenetic markers: complex molecular karyotypes (98.1% vs 45.2%), 1p loss (50.0% vs 20.2%), t(4;14) (20.4% vs 7.7%), 8p loss (37.0% vs 15.0%), 13/13q loss (70.4% vs 41.7%), and 17p loss (33.3% vs 6.5%). The size and location of 12p losses were heterogeneous with a common 0.88 Mb minimally deleted region that included ~9 genes from ETV6 to CDKN1B in 52/54 (~96.3%) patients but did not include CD27. Our findings support 12p loss being a secondary chromosome abnormality frequently co-occurring with adverse cytogenetic markers and complex molecular karyotypes indicative of chromosome instability.

Amplification of the Melanocortin-1 Receptor in Nephrotic Syndrome Identifies a Target for Podocyte Cytoskeleton Stabilization.

The melanocortin-1 receptor (MC1R) in podocytes has been suggested as the mediator of the ACTH renoprotective effect in patients with nephrotic syndrome with the mechanism of action beeing stabilization of the podocyte actin cytoskeleton. To understand how melanocortin receptors are regulated in nephrotic syndrome and how they are involved in restoration of filtration barrier function, melanocortin receptor expression was evaluated in patients and a rat model of nephrotic syndrome in combination with cell culture analysis. Phosphoproteomics was applied and identified MC1R pathways confirmed using biochemical analysis. We found that glomerular MC1R expression was increased in nephrotic syndrome, both in humans and in a rat model. A MC1R agonist protected podocytes from protamine sulfate induced stress fiber loss with the top ranked phoshoproteomic MC1R activated pathway beeing actin cytoskeleton signaling. Actin stabilization through the MC1R consisted of ERK1/2 dependent phosphorylation and inactivation of EGFR signaling with stabilization of synaptopodin and stressfibers in podocytes. These results further explain how patients with nephrotic syndrome show responsiveness to MC1R receptor activation by decreasing EGFR signaling and as a consequence restore filtration barrier function by stabilizing the podocyte actin cytoskeleton.

Who is and isn't having babies with Down syndrome in western Sydney: a ten year hospital cohort study.

BACKGROUND: Screening for Down syndrome (DS) is a key component of antenatal care, recommended to be universally offered to women irrespective of age or background. Despite this, the diagnosis of DS is often not made until the neonatal period. AIMS: To retrospectively describe and compare the differences in populations with an antenatal diagnosis (AD) and neonatal diagnosis (ND) of DS and to explore why an antenatal diagnosis was not made. MATERIALS AND METHODS: The cohorts were women cared for at Westmead Hospital whose pregnancy received a diagnosis of DS between 2006 and 2015. The demographic variables of the AD and ND cohorts were examined and reasons why an antenatal diagnosis was not made in the ND cohort were analysed. RESULTS: There were 127 diagnoses of DS in the 10-year period, of which 41% were in the ND cohort (n = 52) and 59% in the AD (n = 75). Declaring a religious affiliation rather than Nil Religion was significantly more common in the ND cohort (88.5%) and especially the ND sub-cohort who declined DS screening/testing (95.8%) than the AD cohort (72%, P < 0.05). Women who were not offered screening were significantly younger (P < 0.001) than those who were, with 69% and 20% being ≤30 years, respectively. CONCLUSIONS: The proportion of DS pregnancies diagnosed in the antenatal period in western Sydney could be increased by ensuring younger women are not falsely reassured that DS screening is unnecessary for them. While religious affiliation may be a factor when women decline screening, ensuring appropriate counselling remains important.

A Paediatric Acute Promyelocytic Leukaemia Patient Harbouring a Cryptic PML-RARA Insertion due to a Complex Structural Chromosome 17 Rearrangement.

Acute promyelocytic leukaemia with PML-RARA fusion is usually associated with the t(15;17)(q24.1;q21.1) translocation but may also arise from complex or cryptic rearrangements. The fusion usually resides on chromosome 15 but occasionally on others. We describe a cryptic PML-RARA fusion within a novel chromosome 17 rearrangement. We performed interphase fluorescence in situ hybridisation (FISH) using a dual-fusion PML-RARA probe, followed by reverse transcriptase-polymerase chain reaction (RT-PCR) for PML-RARA, karyotyping, and metaphase FISH using RARA break-apart, locus-specific, and subtelomere probes for chromosome 17. An 850K SNP microarray was also employed. Interphase and metaphase FISH showed atypical results involving a single PML-RARA fusion, no second fusion, but instead separate diminished PML and RARA signals. RT-PCR confirmed PML-RARA fusion; however, karyotyping detected only an altered chromosome 17. Metaphase FISH showed the single fusion and diminished 5' RARA signals located unexpectedly in the subtelomeric short-arm and long-arm regions of the rearranged chromosome 17, respectively. SNP microarray revealed no copy number abnormality. This paediatric patient with PML-RARA fusion reflects a cryptic insertion that resides within a complex and novel chromosome 17 rearrangement. This rearrangement likely arose via 7 chromosome breaks with the insertion occurring first followed by sequential paracentric and then pericentric inversions.

Pexmetinib: A Novel Dual Inhibitor of Tie2 and p38 MAPK with Efficacy in Preclinical Models of Myelodysplastic Syndromes and Acute Myeloid Leukemia.

Myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) suppress normal hematopoietic activity in part by enabling a pathogenic inflammatory milieu in the bone marrow. In this report, we show that elevation of angiopoietin-1 in myelodysplastic CD34(+) stem-like cells is associated with higher risk disease and reduced overall survival in MDS and AML patients. Increased angiopoietin-1 expression was associated with a transcriptomic signature similar to known MDS/AML stem-like cell profiles. In seeking a small-molecule inhibitor of this pathway, we discovered and validated pexmetinib (ARRY-614), an inhibitor of the angiopoietin-1 receptor Tie-2, which was also found to inhibit the proinflammatory kinase p38 MAPK (which is overactivated in MDS). Pexmetinib inhibited leukemic proliferation, prevented activation of downstream effector kinases, and abrogated the effects of TNFα on healthy hematopoietic stem cells. Notably, treatment of primary MDS specimens with this compound stimulated hematopoiesis. Our results provide preclinical proof of concept for pexmetinib as a Tie-2/p38 MAPK dual inhibitor applicable to the treatment of MDS/AML. Cancer Res; 76(16); 4841-9. ©2016 AACR.

Recurrent BCOR Internal Tandem Duplication and YWHAE-NUTM2B Fusions in Soft Tissue Undifferentiated Round Cell Sarcoma of Infancy: Overlapping Genetic Features With Clear Cell Sarcoma of Kidney.

Soft tissue undifferentiated round cell sarcoma (URCS) occurring in infants is a heterogenous group of tumors, often lacking known genetic abnormalities. On the basis of a t(10;17;14) karyotype in a pelvic URCS of a 4-month-old boy showing similar breakpoints with clear cell sarcoma of kidney (CCSK), we have investigated the possibility of shared genetic abnormalities in CCSK and soft tissue URCS. Most CCSKs are characterized by BCOR exon 16 internal tandem duplications (ITDs), whereas a smaller subset shows YWHAE-NUTM2B/E fusions. Because of overlapping clinicopathologic features, we have also investigated these genetic alterations in the so-called primitive myxoid mesenchymal tumor of infancy (PMMTI). Among the 22 infantile URCSs and 7 PMMTIs selected, RNA sequencing was performed in 5 and 2 cases, with frozen tissue, respectively. The remaining cases with archival material were tested for YWHAE-NUTM2B/E by fluorescence in situ hybridization (FISH) or reverse transcription-polymerase chain reaction (RT-PCR), and BCOR ITD by PCR. A control group of 4 CCSKs and 14 URCSs in older children or adults without known gene fusion and 20 other sarcomas with similar histomorphology or age at presentation were also tested. A YWHAE-NUTM2B fusion was confirmed in the index case by FISH and RT-PCR, whereas BCOR ITD was lacking. An identical YWHAE-NUTM2B fusion was found in another URCS case of a 5-month-old girl with a back lesion. The remaining cases and control group lacked YWHAE gene rearrangements; instead, consistent BCOR ITDs, similar to CCSK, were found in 15/29 (52%) infantile sarcoma cases (9/22 infantile URCS and 6/7 PMMTI). In the control cohort, BCOR ITD was found only in 3 CCSK cases but not in the other sarcomas. Histologically, URCS with both genotypes and PMMTI shared significant histologic overlap, with uniform small blue round cells with fine chromatin and indistinct nucleoli. A prominent capillary network similar to CCSK, rosette structures, and varying degree of myxoid change were occasionally seen. BCOR ITD-positive tumors occurred preferentially in the somatic soft tissue of the trunk, abdomen, and head and neck, sparing the extremities. RNAseq showed high BCOR mRNA levels in BCOR ITD-positive cases, compared with other URCSs. In summary, we report recurrent BCOR exon 16 ITD and YWHAE-NUTM2B fusions in half of infantile soft tissue URCS and most PMMTI cases, but not in other pediatric sarcomas. These findings suggest a significant overlap between infantile URCS and CCSK, such as age at presentation, histologic features, and genetic signature, thus raising the possibility of a soft tissue counterpart to CCSK.

Molecular genetic studies of complete hydatidiform moles.

Complete hydatidiform moles (CHM) are abnormal pregnancies with no fetal development resulting from having two paternal genomes with no maternal contribution. It is important to distinguish CHM from partial hydatidiform moles, and non-molar abortuses, due to the increased risk of gestational trophoblastic neoplasia. We evaluated a series of products of conception (POC) (n=643) investigated by genome-wide microarray comparative genomic hybridisation (CGH) with the aim of refining our strategy for the identification of complete moles. Among 32 suspected molar pregnancies investigated by STR genotyping to supplement microarray CGH testing, we found 31.3% (10/32) CHM; all identified among 3.6% (10/272) early first trimester POC. We suggest that when using microarray CGH that genotyping using targeted STR analysis should be performed for all POC referrals to aid in the identification of CHM.

Serum cystatin C levels in children with sickle cell disease.

Patients with sickle cell disease (SCD) may develop kidney dysfunction from childhood. The purpose of this study was to examine the value of serum cystatin C as a marker for glomerular filtration rate (GFR) in children with SCD, as compared to serum creatinine and creatinine clearance (CrCl). Twenty children (ages 9-21, ten males) with SCD with and without albuminuria were studied. The mean serum cystatin for the whole group was 0.89 mg/l (0.5-1.7 mg/l). Mean serum cystatin C was significantly different among the children with proteinuria (n=4), microalbuminuria (n=5), and without albuminuria (n=11) (1.25 mg/l, 0.84 mg/l, and 0.78 mg/l, respectively). The mean GFR derived from serum cystatin was significantly different among these subgroups, becoming abnormal in the proteinuric cohort (63 ml/min per 1.73 m2), in contrast to 94 for the microalbuminuric, and 103 for the normal subgroups. Serum creatinine (mean: 0.58 mg/dl, range: 0.3-1.1) did not change significantly with the level of albuminuria. Mean CrCl remained normal to increased within the subgroups, (133 ml/min per 1.73 m2 for those with proteinuria, 144 for those with microalbuminuria, and 163 for the normal subgroup). We conclude that serum cystatin C correlates with the level of albuminuria and may be a reliable method to measure renal function in SCD.