A230 A MISSENSE MUTATION IN GOBLET CELL PROTEIN FCGBP ALTERS THE GLYCOMIC PROFILE AND FUNCTION OF THE COLONIC MUCUS BARRIER

Background

MUC2 mucin, produced by colonic goblet cells, forms a mucus bilayer that provides a physical barrier between potential pathogens in the lumen and the underlying epithelial cells. Mucus is thus the first line of innate host defense in the gastrointestinal (GI) tract. Many GI diseases including inflammatory bowel disease and colon cancer affect the glycosylation of mucus. Goblet cells produce a variety of proteins that are associated with the mucus layer. Of these proteins, FCGBP is of significant interest due to its structural similarities to MUC2 mucin with unknown functions. In this study, we investigated how a missense mutation in FCGBP altered the glycosylation of goblet cell MUC2 and affected its barrier functions.

Purpose

Hypothesis: A missense mutation in FCGBP results an impaired mucus layer by the altering glycomic profiles of goblet cell mucins. Specific aims:

1) To determine mechanistically how FCGBP impeded the structural integrity of the mucus layer

2) To quantify MUC2 glycoprotein modifications in the altered mucus layer

Method

To investigate whether FCGBP impaired mucus barrier functions, two cell types were investigated: wildtype LS174T (WT) MUC2 mucus-producing goblet cells and LS174T cells with a missense mutation in FCGBP (FCGBP MS). To determine if FCGBP MS led to loss in barrier function in the mucus layer, the penetration of 0.2, 1, and 2 μm fluorescent beads (to mimic bacteria) through the mucus layer were quantified. To determine if the differences in penetrability were caused by differences in MUC2 glycosylation in the goblet cell lines, sensitive glycomic analyses were performed by high-performance liquid chromatography-mass spectrometry (HPLC-MS) and capillary electrophoresis with laser-induced fluorescence detection (CE-LIF). Both intact cells and isolated MUC2 mucin granules were analyzed. To determine if differences in the glycomic profiles was caused by differences in glycotransferases, RT-PCR was performed on over 30 human glycosyltransferases.

Result(s)

FCGBP MS cells exhibited significant loss in MUC2 mucus barrier function as quantified by fluorescent beads penetration through the mucus layer in a temporal manner. FCGBP MS cells exhibited an altered glycomic profile with a notable increase in sialylated glycans as quantified by HPLC-MS. The increase in sialylated glycans was associated with a significant increase in sialyl-transferase expression in FCGBP MS cells.

Conclusion(s)

These data demonstrate that a single missense mutation in FCGBP altered the penetrability of the mucus layer associated with an increase in sialylated proteins, a signature hallmark of numerous colonic diseases. FCGBP was critical in providing structural integrity of the mucus layer and maintenance of goblet cell glycosylation profiles.

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CIHR

Disclosure of Interest

None Declared

A70 FECAL-ADHERENT MUCUS IS A NON-INVASIVE SOURCE OF PRIMARY HUMAN MUC2 FOR STRUCTURAL AND FUNCTIONAL CHARACTERIZATION IN HEALTH AND DISEASE

Background

The gel-forming O-glycoprotein Mucin-2 (MUC2) is a key mediator of host-microbe homeostasis in part by forming a barrier to segregate inflammatory microbes from distal colon tissues. While animal models have provided insights into how Muc2 functions, relatively few studies have explored human MUC2. This is due to difficulty in accessing primary MUC2 which has been traditionally seen as firmly adherent to tissues and thus attainable mainly through invasive approaches (e.g. surgery, biopsies, etc), or via transformed cell lines (e.g. LS174T). This highlights a need to find alternative sources of MUC2.

Purpose

The purpose of this study is to develop a non-invasive method to analyze human MUC2 from healthy persons and determine if this can be applied to disease states. Recent studies have shown a significant portion of MUC2 is bound to feces (Bergstrom and Shan et al, 2020). We therefore reasoned this fecal MUC2 was accessible for both purification and structural and functional characterization.

Method

We purified MUC2 from feces via established extraction methods used for tissues. The mucins were resolved by composite urea agarose polyacrylamide gel electrophoresis (UreaAgPAGE) and analyzed by in-gel staining with Alcian Blue (AB), or Western blot for lectins and MUC2. Mucins were subjected to both proteomics to confirm enrichment of MUC2; and O-glycomics via non-reductive ammonia-catalyzed β-elimination followed by capillary electrophoresis (CE) and mass spectrometry in parallel with Type III porcine gastric mucin (PGM) O-glycans for comparison. Purified O-glycans were tested functionally via microbial growth assays with Bacteroides spp, and the ability to be metabolized into short-chain fatty acids (SCFA). Mucus barrier function was also visualized directly on Carnoy's-fixed paraffin-embedded (CFPE) fecal sections followed by dual staining for bacteria by FISH, and MUC2 and/or lectins.

Result(s)

Confocal imaging of CFPE fecal sections revealed a microbiota-encapsulating barrier layer of varying thickness among various healthy human subjects. UreaAgPAGE showed high molecular weight bands (~1 – 2 MDa) by AB staining. Proteomics and western analysis confirmed MUC2 enrichment in fecal mucin preparations. Western analysis via a lectin panel showed human MUC2 bound several lectins but was notably lacking in signal for Sambucus nigra lectin (SNA; α2,6-linked sialic acid) or Ulex europaeus agglutinin I (UEA1; α1,2-linked fucose). O-glycomics revealed extensive sialylation, moderate sulfation, and very little fucosylation vs. PGM. Functionally, the glycans supported growth of Bacteroides thetaiotaomicron as well as B.theta-dependent SCFA production in vitro. Pilot studies with human Ulcerative Colitis (UC) showed intact MUC2 with a differential O-glycosylation profile by glycan "fingerprinting" via CE.

Conclusion(s)

These studies highlight a new way to access primary human MUC2 for downstream functional analyses and pave the way for characterizing MUC2 dysfunction in diseases including IBD.

Disclosure of Interest

None Declared

A71

SIGNIFICANT RACIAL/ETHNIC DIFFERENCES EXIST IN THE RECEIPT OF IBD-RELATED SURGERY

A SYSTEMATIC REVIEW AND META-ANALYSIS

T. Chhibba^*, P. Tandon, N. Natt, G. Brar, G. Malhi, G. Nguyen

Background

Patients with inflammatory bowel disease (IBD) may require surgical intervention for management of their disease. There is a rising incidence of IBD in racial and ethnic minorities but studies regarding healthcare utilization patterns in these populations have yielded variable results.

Purpose

We aimed to examine the differences in surgical rates of ethnic and racial groups compared to White patients with IBD.

Method

Electronic databases were searched through December 20, 2021. Studies that compared ulcerative colitis (UC) or Crohn’s disease (CD) surgery rates between different racial/ethnic groups were included. Both pediatric and adult studies were included. Pooled event rates were generated and p-value < 0.05 was considered statistically significant in generating odds ratios (OR) with 95% confidence interval (CI). We also compared differences in disease location, phenotype, and IBD-medication exposure amongst different groups included.

Result(s)

Forty-one studies stratified rates of IBD-related surgeries by race or ethnicity (n=1,094,693 patients). Black patients were less likely to undergo IBD-related surgeries compared to White patients (pooled OR 0.70, 95% CI, 0.55-0.89, I2=87.0%). Black patients were also less likely compared to White patients to undergo an emergent colectomy with an incidence rate ratio of 0.43 (95% CI, 0.32-0.58). Furthermore, Hispanic patients were less likely to undergo a CD-related surgery (pooled OR 0.57, 95% CI, 0.48-0.68, I2=0%) compared to White patients. Finally, Asian patients had no significant difference in likelihood of CD-related and UC-related surgeries compared to White patients. Black patients were more likely to have perianal disease (pooled OR 1.40, 95% CI, 1.06-1.86), I2=58.2%) but otherwise disease characteristics and phenotypes were similar across all populations compared to Caucasians.

Conclusion(s)

Black and Hispanic patients with IBD are less likely to have surgery, including emergent surgery, for IBD compared to White patients with IBD, despite similar disease phenotype characteristics. Disparities in access to care may be contributory toward these findings and efforts should be made to provide equitable care to all persons living with IBD, regardless of race and ethnicity.

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Other

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Nil

Disclosure of Interest

None Declared

A21 ROLE OF SIALIC ACID O-ACETYLATION IN MAINTAINING MUCUS INTEGRITY AND HOMEOSTASIS OF THE COLONIC MUCOSA

Background

The mucus network provides innate immune defense to protect our gastrointestinal tract from pathogens, and promote homeostasis with our resident microbiota. This network is constituted by the mucin MUC2 (Muc2 in mouse), which is ~80% complex O-linked glycans by weight. Sialic acid (Sia) is a key capping monosaccharide on complex O-glycans which has recently been linked to preserving mucus integrity. Sia can undergo enzymatic modifications including the addition of O-acetyl groups. The 9-O-acetyltransferase CasD1 is responsible for the 9-OAc Sia variants. Functionally, the OAc-modification is known to inhibit microbial sialidase activities which may preserve Sia’s protective roles on mucins. However, the extent of these OAc modifications in human and murine Mucin-2, and how they influence mucus function is unclear.

Purpose: To determine whether and how Sia O-acetylation on colonic mucus regulates mucus integrity, host-microbe interactions, and colitis susceptibility.

Method

We used viral-derived probes that target specific OAc-Sia analogues on mucus on sections from human feces and mouse feces and colon tissues to visualize their spatial arrangement and microbial interaction in situ. For glycomics, OAc-Sia analogues were quantitated on purified human MUC2 and mouse Muc2 by HPLC-MS after derivatization with 4,5-dimethyl-1,2-diaminobenzamine (DMBA). O-glycans were released via non-reductive ammonia-catalyzed β-elimination and analyzed by mass spectrometry. For in vivo work, we generated intestinal epithelial cell-specific Casd1 KO mice (Casd1^flox/flox;VillinCre or IEC Casd1^-/- mice) and analyzed their mucins. Sialidase activities were quantified in the supernatants of colon fecal materials from WT and IEC Casd1^-/- mutants mice using a fluorogenic substrate 4-MU-NeuNAc. Colitis susceptibility was monitored using 1.5% w/v Dextran Sodium Sulfate (DSS).

Result(s)

We found Sias on both human MUC2 and murine Muc2 were heavily O-acetylated, with ~75% and ~45% of Sias having 9-OAc-based modification in humans and mice respectively, and were distributed throughout the niche and barrier layers of mucus in situ. IEC Casd1^-/- mice were viable and healthy with knockdown confirmed by 9-OAc staining, western blot of protein lysates and mucins, and sialylomics. The mucus encapsulation appeared overall intact regardless of OAc status. However, IEC Casd1^-/- mice showed heightened susceptibility to 1.5% DSS colitis, linked to thinning of the mucus in IEC Casd1^-/- vs WT littermates after challenge. Consistent with the role of OAc Sia in sialidase inhibition, loss of OAc Sia was associated with increased sialidase activities as assessed by heightened 4 MU signal in fecal supernatants in WT vs littermate IEC Casd1^-/- mice. O-glycomics also showed reduction in the number of sialylated O-glycan structures upon loss of 9-OAc Sia.

Conclusion(s)

Sia O-acetylation appears important in maintaining key aspects of Sia-dependent mucus function and protecting from inflammatory insult.

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Disclosure of Interest

None Declared

Germline genetic mutations in pediatric cerebrovascular anomalies: a multidisciplinary approach to screening, testing, and management

OBJECTIVE

Genetic alterations are increasingly recognized as etiologic factors linked to the pathogenesis and development of cerebrovascular anomalies. Their identification allows for advanced screening and targeted therapeutic approaches. The authors aimed to describe the role of a collaborative approach to care and genetic testing in pediatric patients with neurovascular anomalies, with the objectives of identifying what genetic testing recommendations were made, the yield of genetic testing, and the implications for familial screening and management at present and in the future.

METHODS

The authors performed a descriptive retrospective cohort study examining pediatric patients genetically screened through the Pediatric Neurovascular Program of a single treatment center. Patients 18 years of age and younger with neurovascular anomalies, diagnosed radiographically or histopathologically, were evaluated for germline genetic testing. Patient demographic data and germline genetic testing and recommendation, clinical, treatment, and outcome data were collected and analyzed.

RESULTS

Sixty patients were included; 29 (47.5%) were female. The mean age at consultation was 11.0 ± 4.9 years. Diagnoses included cerebral arteriovenous malformations (AVMs) (n = 23), cerebral cavernous malformations (n = 19), non-neurofibromatosis/non-sickle cell moyamoya (n = 8), diffuse cerebral proliferative angiopathy, and megalencephaly-capillary malformation. Of the 56 patients recommended to have genetic testing, 40 completed it. Genetic alterations were found in 13 (23%) patients. Four patients with AVMs had RASA1, GDF2, and ACVRL1 mutations. Four patients with cavernous malformations had Krit1 mutations. One with moyamoya disease had an RNF213 mutation. Three patients with megalencephaly-capillary malformation had PIK3CA mutations, and 1 patient with a cavernous sinus lesion had an MED12 mutation. The majority of AVM patients were treated surgically. Patients with diffuse cerebral proliferative angiopathy were treated medically with sirolimus. At-risk relatives of 3 patients positive for genetic anomalies had also been tested.

CONCLUSIONS

This study demonstrates a role for exploring genetic alterations in the identification and treatment of pediatric neurovascular disease pathogenesis. Germline genetic mutations were found in almost one-quarter of the patients screened in this study, results that helped to identify medically targeted treatment modalities for some pediatric neurovascular patients. Insight into the genetic etiology of vascular anomalies may provide broader clinical implications for risk assessment, family screening, follow-up surveillance, and medical management.

Diagnostic work-up for severe aplastic anemia in children: Consensus of the North American Pediatric Aplastic Anemia Consortium

The North American Pediatric Aplastic Anemia Consortium (NAPAAC) is a group of pediatric hematologist-oncologists, hematopathologists, and bone marrow transplant physicians from 46 institutions in North America with interest and expertise in aplastic anemia, inherited bone marrow failure syndromes, and myelodysplastic syndromes. The NAPAAC Bone Marrow Failure Diagnosis and Care Guidelines Working Group was established with the charge of harmonizing the approach to the diagnostic workup of aplastic anemia in an effort to standardize best practices in the field. This document outlines the rationale for initial evaluations in pediatric patients presenting with signs and symptoms concerning for severe aplastic anemia.

Homozygous GDF2 nonsense mutations result in a loss of circulating BMP9 and BMP10 and are associated with either PAH or an "HHT-like" syndrome in children

Background

Disrupted endothelial BMP9/10 signaling may contribute to the pathophysiology of both hereditary hemorrhagic telangiectasia (HHT) and pulmonary arterial hypertension (PAH), yet loss of circulating BMP9 has not been confirmed in individuals with ultra‐rare homozygous GDF2 (BMP9 gene) nonsense mutations. We studied two pediatric patients homozygous for GDF2 (BMP9 gene) nonsense mutations: one with PAH (c.[76C>T];[76C>T] or p.[Gln26Ter];[Gln26Ter] and a new individual with pulmonary arteriovenous malformations (PAVMs; c.[835G>T];[835G>T] or p.[Glu279Ter];[Glu279Ter]); both with facial telangiectases.

Methods

Plasma samples were assayed for BMP9 and BMP10 by ELISA. In parallel, serum BMP activity was assayed using an endothelial BRE‐luciferase reporter cell line (HMEC1‐BRE). Proteins were expressed for assessment of secretion and processing.

Results

Plasma levels of both BMP9 and BMP10 were undetectable in the two homozygous index cases and this corresponded to low serum‐derived endothelial BMP activity in the patients. Measured BMP9 and BMP10 levels were reduced in the asymptomatic heterozygous p.[Glu279Ter] parents, but serum activity was normal. Although expression studies suggested alternate translation can be initiated at Met57 in the p.[Gln26Ter] mutant, this does not result in secretion of functional BMP9.

Conclusion

Collectively, these data show that homozygous GDF2 mutations, leading to a loss of circulating BMP9 and BMP10, can cause either pediatric PAH and/or “HHT‐like” telangiectases and PAVMs. Although patients reported to date have manifestations that overlap with those of HHT, none meet the Curaçao criteria for HHT and seem distinct from HHT in terms of the location and appearance of telangiectases, and a tendency for tiny, diffuse PAVMs.

Expansion of germline RPS20 mutation phenotype to include Diamond-Blackfan anemia

Diamond-Blackfan anemia (DBA) is a ribosomopathy of variable expressivity and penetrance characterized by red cell aplasia, congenital anomalies, and predisposition to certain cancers, including early-onset colorectal cancer (CRC). DBA is primarily caused by a dominant mutation of a ribosomal protein (RP) gene, although approximately 20% of patients remain genetically uncharacterized despite exome sequencing and copy number analysis. Although somatic loss-of-function mutations in RP genes have been reported in sporadic cancers, with the exceptions of 5q-myelodysplastic syndrome (RPS14) and microsatellite unstable CRC (RPL22), these cancers are not enriched in DBA. Conversely, pathogenic variants in RPS20 were previously implicated in familial CRC; however, none of the reported individuals had classical DBA features. We describe two unrelated children with DBA lacking variants in known DBA genes who were found by exome sequencing to have de novo novel missense variants in RPS20. The variants affect the same amino acid but result in different substitutions and reduce the RPS20 protein level. Yeast models with mutation of the cognate residue resulted in defects in growth, ribosome biogenesis, and polysome formation. These findings expand the phenotypic spectrum of RPS20 mutation beyond familial CRC to include DBA, which itself is associated with increased risk of CRC.

Exome sequencing disclosures in pediatric cancer care: Patterns of communication among oncologists, genetic counselors, and parents

OBJECTIVE

To examine communication patterns and behaviors during disclosure of exome sequencing (ES) results to parents of pediatric cancer patients, and describe common themes in parental communication.

METHODS

Using mixed methods, we analyzed transcripts of sessions where parents of pediatric cancer patients received ES results from an oncologist and genetic counselor. Seventy-six transcripts were analyzed for frequency of clinician information-giving, partnering-supportive talk, and active parent participation. A subset of 40 transcripts were analyzed using thematic content analysis.

RESULTS

Disclosures consisted mostly of clinician talk (84% of total talk), which was focused on providing information (62% of clinicians' utterances) with occasional partnering-supportive talk (7% of clinicians' utterances). Most parents assumed a passive, listening role (16% of total talk). Themes in parental communication included expressing relief and the significance of an answer, concern about sharing results and responsibility for inheritance, and seeking clarification of health implications of results.

CONCLUSION

Our finding of low levels of active parent participation during ES disclosures highlights the need to improve patient/parent engagement and understanding in a genetic setting.

PRACTICE IMPLICATIONS

Clinician communication strategies that could encourage parent participation and understanding include checking for parent understanding, partnership-building, and tailoring ES discussions to address parent concerns and preferences.

PSTPIP1-associated myeloid-related proteinemia inflammatory syndrome: A rare cause of childhood neutropenia associated with systemic inflammation and hyperzincemia

Neutropenia in pediatric patients can be due to a variety of disorders. We describe two patients who underwent extensive evaluation over many years for arthralgias and moderate neutropenia of unclear etiology. Genetic testing identified a pathogenic variant in PSTPIP1 (proline-serine-threonine phosphatase-interacting protein 1) in both patients. Markedly elevated inflammatory markers and zinc levels confirmed the rare diagnosis of PSTPIP1-associated myeloid-related proteinemia inflammatory (PAMI) syndrome, tailoring treatment. Neutropenia is common in patients with PAMI syndrome. Unique mutations seen in PAMI syndrome may account for the specific phenotypic features of this disorder.

Approaches to carrier testing and results disclosure in translational genomics research: The clinical sequencing exploratory research consortium experience

Background

Clinical genome and exome sequencing (CGES) is primarily used to address specific clinical concerns by detecting risk of future disease, clarifying diagnosis, or directing treatment. Additionally, CGES makes possible the disclosure of autosomal recessive and X‐linked carrier results as additional secondary findings, and research about the impact of carrier results disclosure in this context is needed.

Methods

Representatives from 11 projects in the clinical sequencing exploratory research (CSER) consortium collected data from their projects using a structured survey. The survey focused on project characteristics, which variants were offered and/or disclosed to participants as carrier results, methods for carrier results disclosure, and project‐specific outcomes. We recorded quantitative responses and report descriptive statistics with the aim of describing the variability in approaches to disclosing carrier results in translational genomics research projects.

Results

The proportion of participants with carrier results was related to the number of genes included, ranging from 3% (three genes) to 92% (4,600 genes). Between one and seven results were disclosed to those participants who received any positive result. Most projects offered participants choices about whether to receive some or all of the carrier results. There were a range of approaches to communicate results, and many projects used separate approaches for disclosing positive and negative results.

Conclusion

Future translational genomics research projects will need to make decisions regarding whether and how to disclose carrier results. The CSER consortium experience identifies approaches that balance potential participant interest while limiting impact on project resources.

Undergraduate Student Perceptions and Awareness of Genetic Counseling

Genetic counseling is a rapidly expanding field, and the supply of certified genetic counselors is currently unable to keep up with job demand. Research is fairly limited regarding the awareness and perceptions that prospective genetic counseling students have on the field and what factors most influence their interest. The current study includes data collected from 1389 undergraduate students in the sciences at 23 universities across the United States who were surveyed regarding information related to their awareness, perceptions, knowledge, and interest in genetic counseling. The majority of participants had heard of genetic counseling (78.0%), many from a high school course (37.3%), college course (28.1%), or online (11.5%). Familiarity was associated with factors such as female gender (p = 0.003) and length of time in school (p < 0.001). After taking the survey, participant interest was positively associated with several factors including female gender (p < 0.001) and Asian and Hispanic ethnicity (p = 0.012). Factors commonly reported as attractive about the field included direct patient care, the variety of roles available, cultural competency and psychosocial training, and helping others. Discussion elaborates upon specific factors related to student awareness and interest in genetic counseling and potential ways to tailor recruitment strategies for maximum benefit to the field.

Integrated tumor and germline whole-exome sequencing identifies mutations in MAPK and PI3K pathway genes in an adolescent with rosette-forming glioneuronal tumor of the fourth ventricle

The integration of genome-scale studies such as whole-exome sequencing (WES) into the clinical care of children with cancer has the potential to provide insight into the genetic basis of an individual's cancer with implications for clinical management. This report describes the results of clinical tumor and germline WES for a patient with a rare tumor diagnosis, rosette-forming glioneuronal tumor of the fourth ventricle (RGNT). Three pathogenic gene alterations with implications for clinical care were identified: somatic activating hotspot mutations in FGFR1 (p.N546K) and PIK3CA (p.H1047R) and a germline pathogenic variant in PTPN11 (p.N308S) diagnostic for Noonan syndrome. The molecular landscape of RGNT is not well-described, but these data are consistent with prior observations regarding the importance of the interconnected MAPK and PI3K/AKT/mTOR signaling pathways in this rare tumor. The co-occurrence of FGFR1, PIK3CA, and PTPN11 alterations provides further evidence for consideration of RGNT as a distinct molecular entity from pediatric low-grade gliomas and suggests potential therapeutic strategies for this patient in the event of tumor recurrence as novel agents targeting these pathways enter pediatric clinical trials. Although RGNT has not been definitively linked with cancer predisposition syndromes, two prior cases have been reported in patients with RASopathies (Noonan syndrome and neurofibromatosis type 1 [NF1]), providing an additional link between these tumors and the mitogen-activated protein kinase (MAPK) signaling pathway. In summary, this case provides an example of the potential for genome-scale sequencing technologies to provide insight into the biology of rare tumors and yield both tumor and germline results of potential relevance to patient care.

Thrombopoietin Measurement as a Key Component in the Evaluation of Pediatric Thrombocytosis

JAK2, MPL, and CALR mutations, which underlie essential thrombocythemia (ET) in most adults, are infrequent in children. Consequently, additional tests are needed to confirm pediatric ET diagnoses. We report a child with suspected ET and normal JAK2, MPL, and CALR analyses. Serum thrombopoietin (TPO) was markedly elevated, leading to analysis of the TPO gene, TPHO, which contains an upstream open reading frame (uORF) known to repress THPO translation. Sequencing revealed a de novo, germline stopgain mutation in the uORF, explaining the elevated TPO and thrombocytosis. This finding suggests that screening TPO levels and, if elevated, THPO 5' UTR sequencing could be diagnostic.

Diagnostic Yield of Clinical Tumor and Germline Whole-Exome Sequencing for Children With Solid Tumors

Importance

Whole-exome sequencing (WES) has the potential to reveal tumor and germline mutations of clinical relevance, but the diagnostic yield for pediatric patients with solid tumors is unknown.

Objective

To characterize the diagnostic yield of combined tumor and germline WES for children with solid tumors.

Design

Unselected children with newly diagnosed and previously untreated central nervous system (CNS) and non-CNS solid tumors were prospectively enrolled in the BASIC3 study at a large academic children's hospital during a 23-month period from August 2012 through June 2014. Blood and tumor samples underwent WES in a certified clinical laboratory with genetic results categorized on the basis of perceived clinical relevance and entered in the electronic health record.

Main Outcomes and Measures

Clinical categorization of somatic mutations; frequencies of deleterious germline mutations related to patient phenotype and incidental medically-actionable mutations.

Results

Of the first 150 participants (80 boys and 70 girls, mean age, 7.4 years), tumor samples adequate for WES were available from 121 patients (81%). Somatic mutations of established clinical utility (category I) were reported in 4 (3%) of 121 patients, with mutations of potential utility (category II) detected in an additional 29 (24%) of 121 patients. CTNNB1 was the gene most frequently mutated, with recurrent mutations in KIT, TSC2, and MAPK pathway genes (BRAF, KRAS, and NRAS) also identified. Mutations in consensus cancer genes (category III) were found in an additional 24 (20%) of 121 tumors. Fewer than half of somatic mutations identified were in genes known to be recurrently mutated in the tumor type tested. Diagnostic germline findings related to patient phenotype were discovered in 15 (10%) of 150 cases: 13 pathogenic or likely pathogenic dominant mutations in adult and pediatric cancer susceptibility genes (including 2 each in TP53, VHL, and BRCA1), 1 recessive liver disorder with hepatocellular carcinoma (TJP2), and 1 renal diagnosis (CLCN5). Incidental findings were reported in 8 (5%) of 150 patients. Most patients harbored germline uncertain variants in cancer genes (98%), pharmacogenetic variants (89%), and recessive carrier mutations (85%).

Conclusions and Relevance

Tumor and germline WES revealed mutations in a broad spectrum of genes previously implicated in both adult and pediatric cancers. Combined reporting of tumor and germline WES identified diagnostic and/or potentially actionable findings in nearly 40% of newly diagnosed pediatric patients with solid tumors.

Abstract 04: Impact of whole exome sequencing results on clinical decision making for pediatric solid tumor patients in the hypothetical scenario of tumor relapse: A survey of pediatric oncologists

Background: The development of molecularly-targeted agents has made it possible to personalize therapy for patients by targeting the specific mutations in their tumor. Pediatric clinical trials utilizing such strategies are being planned but little is known about the opinions of pediatric oncologists regarding the utility of genomic data for guiding treatment decisions. The goals of this study were to (1) characterize those opinions in the context of children with relapsed/refractory solid tumors and (2) assess the potential impact of clinical whole exome sequencing (WES) data on medical decision-making in that context.

Methods: As part of the ongoing BASIC3 clinical sequencing study at Texas Children's Cancer Center, clinical germline and tumor (if sample available) WES were performed for unselected newly-diagnosed pediatric CNS and non-CNS solid tumor patients. The primary oncologist for each (n=17) received online surveys for each study patient before and after review of WES reports. The pre- and post-WES surveys asked oncologists to rank options for off-study systemic chemotherapy (of any type) for their patient in the hypothetical scenario of tumor relapse. Oncologists were then asked if they would consider using a molecularly-targeted agent in the context of a clinical trial, and if so, which agents (from a representative list), their rank order and the rationale for those choices. Post-WES surveys also included questions regarding perceived utility of the tumor WES results for patient care. Pre-WES surveys were analyzed for baseline oncologist responses regarding these hypothetical treatment decisions. When available, pre- and post-WES surveys were analyzed as pairs as an initial assessment of the influence of the WES results on the oncologist's choice of therapy.

Results: 177/189 (94%) of pre-WES surveys and 111/161 (69%) post-WES surveys were available for analysis. Analysis of pre-exome surveys revealed that oncologists would recommend systemic chemotherapy for 127/177 (72%) patients in the hypothetical event of tumor relapse but would consider a molecularly-targeted agent off-study as their first option in only 8/177 (4%) cases. In contrast, oncologists indicated that they would consider targeted therapies in the context of a clinical trial for 99/177 (56%) patients, most commonly sorafenib (n=21), cixutumumab (n=17), and crizotinib (n=13). There were 26 cases in which somatic mutations were identified in genes categorized as having established or potential clinical relevance, and for which both pre- and post-WES surveys were available. A corresponding targeted agent was ranked for consideration in the hypothetical scenario of relapse on the post-WES survey for 8/26 (31%) of these patients (somatic mutations in MET, JAK2, HRAS, NRAS X 2, ALK, BRAF, KIT), having only been chosen on the pre-WES survey in 2 of those cases. On 8 of 111 (7%) post-WES surveys, the oncologist removed a targeted agent that had been prioritized on the pre-WES survey after no relevant mutation was detected, including the Sonic Hedgehog inhibitor GDC-0449 in 5 cases.

Conclusion: Although genomic tests such as WES have the potential to identify molecular targets for therapy in children with relapsed tumors, a survey of pediatric oncologists revealed that most consider such therapies as options only in the context of a clinical trial. These findings support the potential utility of WES in precision oncology approaches as well as the need for clinical trials evaluating the use of integrated genomic testing to guide treatment of children with relapsed solid tumors.

Citation Format: Abhishek Bavle, Tao Wang, Frank Y. Lin, Angshumoy Roy, Robin A. Kerstein, Sarah Scollon, Katie Bergstrom, Stephanie Gutierrez, Uma Ramamurthy, Yaping Yang, Christine M. Eng, Richard A. Gibbs, Murali M. Chintagumpala, Susan G. Hilsenbeck, Sharon E. Plon, Stacey L. Berg, D. Williams Parsons. Impact of whole exome sequencing results on clinical decision making for pediatric solid tumor patients in the hypothetical scenario of tumor relapse: A survey of pediatric oncologists. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Integrating Clinical Genomics and Cancer Therapy; Jun 13-16, 2015; Salt Lake City, UT. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(1_Suppl):Abstract nr 04.

Abstract IA16: Clinical genomics for children with solid tumors: Current realities and future opportunities

Genome-scale sequencing methods such as whole exome sequencing (WES) have provided significant insight into the pathogenesis of cancer. However, experience with the use of these tests in the clinical care of cancer patients remains limited. Sequencing of tumor and matched normal samples can reveal multiple types of results with implications for clinical practice. The identification of somatic (tumor-specific) mutations has the potential to offer diagnostic and prognostic information and inform selection of therapies. Detection of germline mutations in cancer susceptibility genes may prompt further genetic testing and guide cancer surveillance strategies for both the patient and family members. Germline mutations may also explain non-cancer phenotypes, predict drug responses, or provide reproductive counseling information for parents. The goal of the BASIC3 (Baylor College of Medicine Advancing Sequencing into Childhood Cancer Care) study is to determine the clinical impact of incorporating clinical tumor and constitutional WES into the care of children with newly diagnosed solid tumors. This study follows pediatric patients with newly diagnosed CNS and non-CNS solid tumors at Texas Children's Cancer Center for two years after performing CLIA-certified WES of blood and frozen tumor samples. Results are deposited into the electronic health record and disclosed to families by their oncologist and a genetic counselor. The potential impact of tumor exome findings on clinical decision-making is assessed through review of the medical record over the two year follow-up period as well as through surveys of the oncologists regarding prioritization of treatment options in the hypothetical event of tumor recurrence before and after receiving tumor exome results. Preferences of patient families and oncologists for reporting this complex information are obtained by interviews and audio recording of the WES result disclosure visits. Since the study opened in August 2012, more than 210 subjects have been enrolled (~80% of potentially eligible patients), representing the expected distribution of both CNS and non-CNS tumors. WES results have been reported for 170 subjects, revealing potentially-clinically relevant germline and somatic mutations in cancer genes known to be related to pediatric solid tumors as well as others known to be mutated primarily in adult cancer patients. Data will be presented regarding the diagnostic yield of combined tumor and germline WES for children with newly-diagnosed solid tumors. These results demonstrate the feasibility of routine tumor WES in the pediatric oncology clinic and a significant level of parental interest in receiving WES results and have significant implications for the treatment of children with relapsed and refractory solid tumors and the design of clinical trials using precision oncology approaches for these patients. Further analyses of the clinical utility of the WES data and the preferences of oncologists and parents for reporting of these results are under study. The BASIC3 study is a Clinical Sequencing Exploratory Research (CSER) program project supported by NHGRI/NCI 1U01HG006485.

Citation Format: D. William Parsons, Angshumoy Roy, Yaping Yang, Tao Wang, Sarah Scollon, Katie Bergstrom, Robin A. Kerstein, Stephanie Gutierrez, Abhishek Bavle, Frank Y. Lin, Dolores H. López-Terrada, Federico A. Monzon, Jed G. Nuchtern, Uma Ramamurthy, Amy L. McGuire, Susan G. Hilsenbeck, Jeffrey G. Reid, Donna M. Muzny, David A. Wheeler, Stacey L. Berg, Murali M. Chintagumpala, Christine M. Eng, Richard A. Gibbs, Sharon E. Plon. Clinical genomics for children with solid tumors: Current realities and future opportunities. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Integrating Clinical Genomics and Cancer Therapy; Jun 13-16, 2015; Salt Lake City, UT. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(1_Suppl):Abstract nr IA16.

Pediatric Cancer Genetics Research and an Evolving Preventive Ethics Approach for Return of Results after Death of the Subject

The return of genetic research results after death in the pediatric setting comes with unique complexities. Researchers must determine which results and through which processes results are returned. This paper discusses the experience over 15 years in pediatric cancer genetics research of returning research results after the death of a child and proposes a preventive ethics approach to protocol development in order to improve the quality of return of results in pediatric genomic settings.

Abstract 11: Evaluating cancer susceptibility mutations and incidental findings from whole exome sequencing of sequentially diagnosed pediatric solid and brain tumor patients: Early results of the BASIC3 study

Advances in sequencing technologies allow for provision of genome-scale data to oncologists and geneticists caring for pediatric cancer patients but current experience with the clinical application of genomic sequencing is limited. The goal of the BASIC3 (Baylor Advancing Sequencing into Childhood Cancer Care) study is to determine the clinical impact of incorporating tumor and constitutional whole exome sequencing (WES) into the care of children with newly diagnosed solid tumors at Texas Children's Cancer Center (target enrollment n=280). WES of patient blood and frozen tumor samples was conducted in the CLIA-certified Whole Genome Laboratory at Baylor College of Medicine using the vCrome 2.1 capture platform and Illumina paired-end sequencing. Reported WES germline findings were validated by a second platform and evaluated in parental blood samples if available, then deposited into the electronic medical record and disclosed to families by their oncologist and a genetic counselor. These disclosure visits are audio recorded and transcribed for analysis of the communication of WES results between parents and oncologists; in addition, the parents and oncologists are serially interviewed to determine preferences for reporting this complex information. Since the study opened in August 2012, 80% of 145 potentially eligible families have consented to enrollment. The first 100 patients comprise a diverse representation of diagnoses, including 32 with CNS tumors (32%) and 68 with non-CNS tumors (68%). The germline WES results (n=85 reported to date) included diagnostic findings in 10 cases including 7 patients with pathogenic mutations in dominant cancer susceptibility genes (all singletons except TP53 mutations identified in 2 patients). Only 3 of these 7 patients had genetic testing recommended clinically. There were 2 patients with mutations which identified the genetic cause of other (non-cancer) medical problems, and 1 study patient with mutations which explained both liver disease and hepatocellular carcinoma. Downstream testing of at-risk relatives has occurred rapidly in several families and cancer screening recommendations implemented in patients and family members. Seven medically actionable incidental findings unrelated to clinical phenotype have also been reported, predominantly in cardiovascular genes and mitochondrial DNA. The BASIC3 study demonstrates the feasibility of routine germline WES in the pediatric oncology clinic and a significant level of parental interest in receiving WES results. Early results suggest that clinically relevant susceptibility mutations can be identified in approximately 10% of unselected pediatric solid and brain tumor patients. This is a conservative estimate, as the WES data analysis does not currently report copy number variation in cancer susceptibility genes. A similar proportion of patients had incidental medically actionable mutations reported. The clinical utility of the germline WES data and the preferences of oncologists and parents for reporting of these results are under study. Supported by NHGRI/NCI 1U01HG006485.

Citation Format: Sharon E. Plon, Sarah Scollon, Katie Bergstrom, Robin A. Kerstein, Murali Chintagumpala, Stacey L. Berg, Susan G. Hilsenbeck, Tao Wang, Surya Rednam, David Wheeler, Laurence McCullough, Richard Street, Amy L. McGuire, Reid G. Jeffrey, Donna M. Muzny, Christine M. Eng, Yaping Yang, Richard A. Gibbs, Donald W. Parsons. Evaluating cancer susceptibility mutations and incidental findings from whole exome sequencing of sequentially diagnosed pediatric solid and brain tumor patients: Early results of the BASIC3 study. [abstract]. In: Proceedings of the AACR Special Conference: Cancer Susceptibility and Cancer Susceptibility Syndromes; Jan 29-Feb 1, 2014; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(23 Suppl):Abstract nr 11. doi:10.1158/1538-7445.CANSUSC14-11

Co-inheritance of mild hemophilia A and heterozygosity for type 2N von Willebrand disease: a diagnostic and therapeutic challenge

Hemophilia A and von Willebrand disease are the two most common inherited bleeding disorders. Despite their frequency, however, there are very few reports of co-inheritance of the two disorders. We present the first report of a patient with mild hemophilia A and heterozygosity for type 2N von Willebrand disease (VWD). We discuss the patient's phenotype and highlight the diagnostic and therapeutic challenges caused by this co-inheritance.

Abstract 5169: Diagnostic yield of clinical tumor and germline exome sequencing for newly diagnosed children with solid tumors

Background: Advances in sequencing technologies allow for provision of genome-scale data to physicians caring for pediatric cancer patients but current experience with the clinical application of genomic sequencing is limited and the diagnostic yield of these methods is unclear.

Methods: The goal of the BASIC3 (Baylor Advancing Sequencing into Childhood Cancer Care) study is to determine the clinical impact of incorporating tumor and constitutional whole exome sequencing (WES) into the care of children with newly diagnosed solid tumors at Texas Children's Cancer Center (target enrollment n=280). WES of patient blood and frozen tumor samples is being conducted in the CLIA-certified Whole Genome Laboratory at Baylor College of Medicine using the VCRome 2.1 capture reagent and Illumina paired-end sequencing with reports incorporated in the medical record.

Results: 120 patients have enrolled to date, including 39 (33%) and 81 (67%) with CNS and non-CNS tumors, respectively. Despite limited diagnostic biopsies in many patients, tumor samples adequate for WES have been obtained from 97 subjects (81%). WES results have been reported for 89 patients. Tumor WES (n=73) revealed 20 of 73 tumors (27%) to contain mutations classified as having proven or potential clinical utility, including recurrent alterations of CTNNB1, BRAF, KIT, and NRAS/KRAS. Notably, less than 50% of somatic mutations would have been detected on an adult-focused cancer panel, BCM Cancer Gene Mutation Panel v.2. Germline WES (n=89) identified diagnostic findings in 11 cases (12%) including 8 patients with pathogenic mutations in dominant cancer susceptibility genes (singletons except for 2 patients with TP53 mutations). Four of these 8 patients had genetic testing recommended clinically. There were 2 patients with mutations providing the genetic cause of non-cancer medical problems and 1 patient with a mutation which explained both liver disease and hepatocellular carcinoma. Downstream testing of at-risk relatives has occurred rapidly in several families and cancer screening recommendations implemented. Seven (8%) medically actionable incidental findings unrelated to phenotype were reported, predominantly in cardiovascular genes and mitochondrial DNA.

Conclusions: These data demonstrate the feasibility of routine WES in the pediatric oncology setting. Early results demonstrate that clinically relevant findings are identified by tumor and germline WES in 38% of pediatric solid tumor patients. The yield of clinically relevant somatic and germline alterations would likely increase further by incorporation of complementary genomic methods (e.g. RNA-seq or copy number analysis). Assessment of the clinical utility of the tumor and germline exomes and preferences for reporting of these results to physicians and parents are under study. Supported by NHGRI/NCI 1U01HG006485.

Citation Format: Donald W. Parsons, Angshumoy Roy, Federico A. Monzon, Yaping Yang, Dolores H. López-Terrada, Murali M. Chintagumpala, Stacey L. Berg, Susan G. Hilsenbeck, Tao Wang, Robin A. Kerstein, Sarah Scollon, Katie Bergstrom, Richard L. Street, Laurence B. McCullough, Amy L. McGuire, Uma Ramamurthy, Jeff G. Reid, Donna M. Muzny, David A. Wheeler, Christine M. Eng, Richard A. Gibbs, Sharon E. Plon. Diagnostic yield of clinical tumor and germline exome sequencing for newly diagnosed children with solid tumors. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5169. doi:10.1158/1538-7445.AM2014-5169

Obtaining informed consent for clinical tumor and germline exome sequencing of newly diagnosed childhood cancer patients

BACKGROUND

Effectively educating families about the risks and benefits of genomic tests such as whole exome sequencing (WES) offers numerous challenges, including the complexity of test results and potential loss of privacy. Research on best practices for obtaining informed consent (IC) in a variety of clinical settings is needed. The BASIC3 study of clinical tumor and germline WES in an ethnically diverse cohort of newly diagnosed pediatric cancer patients offers the opportunity to study the IC process in the setting of critical illness. We report on our experience for the first 100 families enrolled, including study participation rates, reasons for declining enrollment, assessment of clinical and demographic factors that might impact study enrollment, and preferences of parents for participation in optional genomics study procedures.

METHODS

A specifically trained IC team offered study enrollment to parents of eligible children for procedures including clinical tumor and germline WES with results deposited in the medical record and disclosure of both diagnostic and incidental results to the family. Optional study procedures were also offered, such as receiving recessive carrier status and deposition of data into research databases. Stated reasons for declining participation were recorded. Clinical and demographic data were collected and comparisons made between enrolled and non-enrolled patients.

RESULTS

Over 15 months, 100 of 121 (83%) eligible families elected to enroll in the study. No significant differences in enrollment were detected based on factors such as race, ethnicity, use of Spanish interpreters and Spanish consent forms, and tumor features (central nervous system versus non-central nervous system, availability of tumor for WES). The most common reason provided for declining enrollment (10% of families) was being overwhelmed by the new cancer diagnosis. Risks specific to clinical genomics, such as privacy concerns, were less commonly reported (5.5%). More than 85% of parents consented to each of the optional study procedures.

CONCLUSIONS

An IC process was developed that utilizes a specialized IC team, active communication with the oncology team, and an emphasis on scheduling flexibility. Most parents were willing to participate in a clinical germline and tumor WES study as well as optional procedures such as genomic data sharing independent of race, ethnicity or language spoken.

Abstract P2-11-16: Cardiac Morbidity After Adjuvant Chemotherapy (CT) for Early Breast Cancer in the Community Setting

Cardiac morbidity after exposure to CT is a known and previously described risk. Anthracycline exposure can be complicated by acute or chronic cardiac toxicity. Trastuzumab exposure is largely associated with acute and reversible cardiac morbidity.

Methods: We retrospectively queried the electronic health record (EHR) from our network of community oncology practices, iKnowMed, for patients (pts) diagnosed with Stage I-III breast cancer (BC) from 2007–2010 with at least 5 visits and follow-up (f/u) through 2012. We stratified this group by CT utilization (yes/no), regimen type, age, and characterized the incidence of cardiac disease or initiation of cardiac medication through the f/u period to determine the association of cardiac disease or treatment with CT utilization. Cardiac diseases analyzed included congestive heart failure, valvular and ischemic heart disease, arrythmias, and hypertension. Cardiac medications included beta blockers, angiotensin-converting-enzyme inhibitors, angiotensin receptor II blockers, loop and thiazide diuretics. Hazard ratios by prespecified risk parameters were then analyzed by multivariate analysis for all pts who did not have cardiac disease preceding their diagnosis of BC.

Results: We identified 20,900 pts with a median f/u of 3.2 yrs (1.4–5.4). 11,295 (54%) pts received adjuvant CT and 9,605 (46%) did not. Median age at diagnosis in the CT-treated arm and non CT-treated arm was 54 and 64 yrs, respectively (p &lt; 0.0001). Among both the non-CT and CT-treated group, the baseline prevalence of cardiac disease was 14%. Among the CT-treated group, 3475 pts or 31% (95% CI, 30 %−32%) had or developed cardiac disease within the study period. In the non-CT group, 3790 pts or 39% (95% CI, 38%−40%) had or developed cardiac disease with the study period (p &lt; 0.01). Receiving CT conveyed a lower risk of cardiac morbidity overall, HR 0.86 (p &lt; 0.01). Incidence of cardiac disease was higher among pts who were in the non-CT treated arm (39%) than among the various CT-treated arms: anthracycline and trastuzumab (30%), anthracycline without trastuzumab (26%), non-anthracycline with trastuzumab (33%), and non-anthracycline without trastuzumab (34%). Incidence of cardiac disease increased proportionally over time in all age groups as expected in both cohorts.

Could automated template based quantification of benzodiazepine receptors in brain single photon emission tomography with 123I NNC 13-8241 be used to demonstrate neuronal damage in traumatic brain injury?

Automated methods are required for the analysis of brain single photon emission tomography images. We applied an automated method to assess the benzodiazepine receptor distribution in the brain. Images of 19 patients with mild traumatic brain injury who had received I NNC 13-8241 were compared with a mean brain template accumulated from 18 healthy volunteers. To obtain more information, we calculated the neuronal benzodiazepine receptor binding in the brain by using pre-defined anatomical regions and a voxel-by-voxel technique. The group of patients with mild traumatic brain injury differed significantly (P =0.015) from the group of healthy volunteers in the distribution of benzodiazepine receptors. This methodological work suggests that a reference based template and a three-dimensional brain model help in regional analysis and quantification and could be useful in demonstrating permanent neuronal damage after head injury.

Highwire regulates synaptic growth in Drosophila

The formation, stabilization, and growth of synaptic connections are dynamic and highly regulated processes. The glutamatergic neuromuscular junction (NMJ) in Drosophila grows new boutons and branches throughout larval development. A primary walking behavior screen followed by a secondary anatomical screen led to the identification of the highwire (hiw) gene. In hiw mutants, the specificity of motor axon pathfinding and synapse formation appears normal. However, NMJ synapses grow exuberantly and are greatly expanded in both the number of boutons and the extent and length of branches. These synapses appear normal ultrastructurally but have reduced quantal content physiologically. hiw encodes a large protein found at presynaptic terminals. Within presynaptic terminals, HIW is localized to the periactive zone surrounding active zones; Fasciclin II (Fas II), which also controls synaptic growth, is found at the same location.

Growth factor usage patterns and outcomes in the community setting: collection through a practice-based computerized clinical information system

PURPOSE

Although use of colony-stimulating factor (CSF) is widespread and guidelines for use have been disseminated, actual practice patterns of medical oncologists are unknown. The purpose of this study was to collect these data using an office-based computerized clinical information system.

PATIENTS AND METHODS

Data were collected on patients at 10 community-based oncology practices. Information regarding CSF use was captured at the time of prescribing through a computerized clinical support tool and stored in a data warehouse, and an analysis was carried out retrospectively.

RESULTS

A total of 6,813 cancer regimens administered to 5,034 patients were evaluated for growth factor use. Overall, CSFs were used in 14% of regimens, with breast, lymphoma, lung, and ovarian being the most common cancers for which CSFs were used. In 49.4% of regimens, CSF was initiated during cycle 1, with an average duration of 1 week, and was used in two or three cycles per regimen. Afebrile neutropenia is rarely followed by CSF initiation. Granulocyte colony-stimulating factor (G-CSF) is associated with fewer dose adjustments, delays, and hospitalizations when compared with granulocyte-macrophage colony stimulating factor (GM-CSF). There is wide variation among oncologists in CSF use, and several substantial differences were noted between the prescribing behavior of American Society of Clinical Oncology (ASCO) survey-reported oncologists and actual clinical practice, as captured by the computerized clinical information system.

CONCLUSION

Computerized clinical information systems can collect detailed information regarding practice patterns of medical oncologists. ASCO physician practice survey data do not accurately reflect actual practice patterns and must be interpreted with caution. Substantial deviations from ASCO growth factor guidelines remain, and oncologists' use of CSFs demonstrates wide variation. There may be important clinical differences between G-CSF and GM-CSF, but definitive phase III trials are needed for confirmation.

Locus of information in words and the right visual field effect

The right visual field (RVF) advantage found for the identification or classification of words has usually been interpreted as evidence for left hemisphere language functions. It has more recently been explained as the result of the fact that the most informative part of the word, presumably the beginning, is in a region of better visual acuity. It is not clear from existing evidence that the beginnings of words are in fact more informative. The present study assessed the locus of information in words by deleting either the initial or terminal one or two letters. Subjects were required to generate a completion. Regardless of whether subjects were scored as correct for generating the original target word (as would be appropriate in a naming study) or for producing any legitimate word (as would be appropriate for a lexical decision study), the results indicated that most words have more information in the initial letters. Nevertheless, there are exceptions to this rule, and some words have more terminal information. Equal numbers of words with more initial information and with more terminal information were selected for two visual field studies in order to assess the effect of the locus of information on visual laterality. In neither a lexical decision study nor a naming study did locus of information affect the commonly observed right visual field superiority. Thus the distribution of information is not likely to be a major confounding variable in laterality studies employing horizontally presented words.

Potentiation of the gonadotoxicity of Cytoxan in the dog by adjuvant treatment with a luteinizing hormone-releasing hormone agonist

This study evaluates the effect on spermatogenesis of coadministration of Cytoxan (cyclophosphamide) and nafarelin, a luteinizing hormone-releasing hormone agonist. Nafarelin causes complete aspermatogenesis in dogs by interrupting the hypothalamic-pituitary-gonadal axis, which might protect against the testicular cytotoxicity associated with cyclophosphamide. The four treatment groups, each consisting of 2 mature male beagle dogs, were (a) no drug; (b) cyclophosphamide (p.o. 3x weekly for 43 and 48 wk for a total dose of 582 and 709 mg/kg, with dose varying according to weekly hematological profile); (c) nafarelin (2 micrograms/kg s.c. daily for 48 and 52 wk); and (d) cyclophosphamide plus nafarelin [same schedule as above with cyclophosphamide (570 and 698 mg/kg total dose) starting 7 wk after beginning nafarelin]. Plasma testosterone, spermatogenesis, and ejaculate volume were completely suppressed by nafarelin prior to starting cyclophosphamide. By 2 wk after cessation of treatment (posttreatment, PT), plasma testosterone reached normal levels, and at 5 wk PT ejaculates appeared which reached normal volumes 2 to 3 wk later. Normally motile ejaculated spermatozoa were noted at 6 to 8 wk PT in nafarelin-only-treated animals; normal sperm numbers were reached at 14 wk PT. The animals receiving cyclophosphamide plus nafarelin were azoospermic for the entire 65-wk PT period, and at 65 wk PT no germinal cells were found upon evaluation of testicular histology. Sperm numbers in cyclophosphamide-only-treated animals began to rise 10-11 wk PT and reached 150 x 10(6) sperm/ejaculate at approximately 65 wk PT (contemporaneous control dogs had sperm numbers of approximately 300-600 x 10(6)/ejaculate). Spermatogenesis in these cyclophosphamide-only-treated animals was normal in most seminiferous tubules at this time. The addition of nafarelin to cyclophosphamide treatment thus exacerbated the deleterious effects of cyclophosphamide on the testes, suggesting caution for use of such a protocol clinically.

Abnormal auditory brain-stem responses in hallucinating schizophrenic patients

Abnormal auditory brain-stem responses (ABRs) were recorded in 10 out of 20 schizophrenic in-patients. The response abnormalities did not show any correlation to the degree of psychopathology, sub-group of schizophrenia, age, sex, or cerebral ventricular enlargement. Nor was there any correlation to previous neuroleptic treatment: a pathological ABR was recorded in 5 of the 8 patients who had never received such medication. A statistically significant relationship was found between ABR pathology and auditory hallucinations: 9 of the 11 patients who admitted having hallucinations exhibited brain-stem response abnormality, whereas ABR abnormality was recorded in only 1 of the 9 patients who denied having hallucinations. The data imply that brain-stem dysfunction is involved in the psychopathology of schizophrenia, and that interference with the auditory pathways in the brain-stem may induce auditory hallucinations in schizophrenic patients.

Peripheral airways function and nonspecific airways reactivity in cigarette smokers

Increasing concentrations of inhaled aerosolized histamine acid phosphate were administered to 31 heavy cigarette smokers from a smoking cessation clinic. Nineteen of 31 smokers (mean age +/- ISD: 39.6 +/- 11.5 yrs; pack years 25.5 +/- 13.5) failed to reduce forced expired volume in one second (FEV1) while inhaling histamine and were labelled nonresponders. In 12 of 31 smokers (age 38.4 +/- 9.4 yrs; pack years 23.0 +/- 10.5), extrapolated provocation concentration of inhaled histamine required to reduce forced expired volume in one second (FEV1) by 10 percent (PC10) could be determined and these smokers were labelled responders. We also measured maximum expiratory flow volume curves with air and also a mixture of 80 percent helium and 20 percent oxygen (HeO2) to determine the percentage of increase in maximal flow at 50 percent vital capacity breathing HeO2 as compared to air (delta Vmax50), and the slope of phase III of the single breath oxygen test (delta N2/L). In the responders, PC10 ranged from 1.4 mg/ml to 10.2 mg/ml (mean 5.5 +/- 3.3 mg/ml) and delta Vmax50 ranged from 7.1 percent to 68.4 percent (mean 39.6 +/- 18.3 percent). There was a significant positive correlation between PC10 and delta Vmax50 (r = 0.77, p less than 0.01), and a significant negative correlation between PC20 and delta N2/L (r = -.61, p less than 0.01). There was no difference between responders and nonresponders in mean values for lung function tests, allergy skin tests, or symptoms. These results suggest that there may be two fundamentally different groups of smokers with peripheral airways dysfunction: one group in which dysfunction is associated with, or related to, airways reactivity, and one group in which dysfunction is related to other factors.

Assessment of a new spermicidal agent against ejaculated dog and human spermatozoa in vitro

The spermatostatic potencies of a new vaginal contraceptive agent, RS-37367, and a standard surfactant compound, nonoxynol-9, have been compared by using ejaculated dog and human spermatozoa. RS-37367 was 25 to 50 times more potent than nonoxynol-9 against dog spermatozoa. Nonparallel concentration-response lines were obtained against human spermatozoa. Concentrations of RS-37367 causing immediate spermatostasis against dog spermatozoa resulted in vesiculation of the plasma and outer acrosomal membranes of spermatozoa; similarly, immediately spermatostatic concentrations of nonoxynol-9 were associated with the previously documented generalized membrane stripping. The activities of both RS-37367 and nonoxynol-9 were affected by the concentration of dog spermatozoa in semen-compound mixtures. Short-term (5-minute) exposure of spermatozoa to concentrations of RS-37367 not immediately spermatostatic resulted in progressive immobilization of spermatozoa. Extensive washing of the spermatozoa was not able to reverse this effect, in contrast to spermatozoa transiently exposed to nonoxynol-9.

Inability of continuous long-term administration of D-Nal(2)6-LHRH to abolish fertility in male rats

A highly potent agonist of LHRH, [6-D-(2-naphthyl)-alanine]-LHRH, was administered chronically for 12 weeks to adult male rats by repetitive implantation of pellets, and its effects upon mating, fertility, and reproductive organ weights have been evaluated. Although significant declines in testicular (P less than 0.001) and epididymidal (P less than 0.001) weights were achieved, no effects on seminal vesicles, prostate, or pituitary weights were observed. After 12 weeks of continuous treatment, three of six agonist-treated rats were still successfully impregnating females. The decline in successful impregnation appeared to be related to the observed reduction in testicular spermatogenesis and in numbers of epididymal spermatozoa. The drug effects appeared reversible, as all six of the agonist-treated rats were fertile by the fifth week after cessation of treatment. Plasma levels of testosterone were markedly elevated immediately after implantation of each pellet and consistently, but not significantly, lowered during the inter-implantation periods. These observations, and the lack of effect on accessory organ weights, are consistent with the maintenance of libido in these treated rats. This is the second demonstration of a selective inhibition of spermatogenesis in the absence of a marked decline in gonadal steroidogenesis with this agent. As in the first demonstration using twice weekly injections, the degree of inhibition of spermatogenesis was insufficient to abolish fertility in the treated male rats.