Citations

1011 Background: Several trials have shown 25-30% pathologic complete response (pCR) rates in patients with HER2+ BC treated with LT therapy (+ endocrine therapy if ER+), but no chemotherapy (CTX). We hypothesize that a multiparameter classifier, comprised of HER2 gene and protein levels, intratumor heterogeneity (ITH), HER2-enriched (E) subtype, and PIK3CA mutation status can identify patients whose tumors are “addicted” to HER2 signaling and are likely to achieve pCR from a CTX-sparing de-escalation strategy. Methods: Baseline specimens from 2 trials (TBCRC023 [NCT00999804] and PAMELA [NCT01973660]) of neoadjuvant CTX-sparing LT (+ endocrine therapy if ER+) in HER2+ BC were used. HER2 protein and ITH (scored for % 3+ by IHC), and gene amplification (HER2:CEP17 ratio and copy number (CN) by CISH) were measured on the same slide by the dual gene protein assay (GPA). HER2-E and PIK3CA mutation status were assessed by research-based PAM50 and MSK-IMPACT platforms, respectively. A decision tree algorithm was used to determine the GPA cutoffs and to construct the classifier of response (by pCR) in TBCRC023, which was then validated in PAMELA. Results: Of the evaluable patients from TBCRC023 (N = 130) and PAMELA (N = 151), GPA data were available for 121 and 94 cases, respectively. Both cohorts exhibited similar distributions for HER2 ratio, CN, and % 3+, and a strong correlation between HER2 ratio and CN (R > 0.92). In TBCRC023, 73 cases had data from GPA, PAM50, and IMPACT, of which 15 had pCR. Recursive partitioning identified cutoffs of HER2 ratio > 4.6 and % 3+ > 97.5% in both the GPA data cohort (N = 121) and complete data cohort (N = 73). With PAM50 and IMPACT data, the model added HER2-E and PIK3CA wild-type (wt). For practical reasons, the classifier was locked as HER2 ratio ≥ 4.5 AND % 3+ ≥ 90% AND PIK3CA-wt AND HER2-E, which yielded a PPV of 55% and NPV of 94%. Validation in PAMELA using 45 cases with data for all 3 assays yielded PPV of 44% and NPV of 82%. 29 TBCRC023 cases without IMPACT data could be predicted to be non-pCR, of which 26 were correct (NPV = 89%). In PAMELA, 66 additional cases could be predicted to be non-pCR, of which 54 were correct (NPV = 81%). Conclusions: We have constructed a multiparameter classifier that can predict pCR with targeted therapy alone that compare to pCR rates of CTX + dual anti-HER2 in unselected patients. Prospective validation in a clinical trial is warranted. [Table: see text]

Abstract Splicing alterations are common in diseases such as cancer, where mutations in splicing factor genes are frequently responsible for aberrant splicing. Here we present an alternative mechanism for splicing regulation in T-cell acute lymphoblastic leukemia (T-ALL) that involves posttranslational stabilization of the splicing machinery via deubiquitination. We demonstrate there are extensive exon skipping changes in disease, affecting proteasomal subunits, cell-cycle regulators, and the RNA machinery. We present that the serine/arginine-rich splicing factors (SRSF), controlling exon skipping, are critical for leukemia cell survival. The ubiquitin-specific peptidase 7 (USP7) regulates SRSF6 protein levels via active deubiquitination, and USP7 inhibition alters the exon skipping pattern and blocks T-ALL growth. The splicing inhibitor H3B-8800 affects splicing of proteasomal transcripts and proteasome activity and acts synergistically with proteasome inhibitors in inhibiting T-ALL growth. Our study provides the proof-of-principle for regulation of splicing factors via deubiquitination and suggests new therapeutic modalities in T-ALL. Significance: Our study provides a new proof-of-principle for posttranslational regulation of splicing factors independently of mutations in aggressive T-cell leukemia. It further suggests a new drug combination of splicing and proteasomal inhibitors, a concept that might apply to other diseases with or without mutations affecting the splicing machinery. This article is highlighted in the In This Issue feature, p. 1241

Abstract Fluorescence in situ hybridization (FISH) is an effective alternative for the analysis of cytogenetic abnormalities of low proliferative entities such as Waldenström macroglobulinemia (WM) but, to date, no studies have been carried out to explore the potential impact of molecular cytogenetics on disease evolution. Deletion of the long arm of chromosome 6 (6q-) is the most frequent cytogenetic abnormality in WM. In this study we have analyzed the incidence of this aberration (using both conventional cytogenetics and FISH analysis) in 102 WM patients, and we have correlated it with disease characteristics. Deletion of 6q21 was detected in 6% of patients by conventional cytogenetics, while FISH studies increased this incidence up to 39%. Moreover, in those patients analyzed by cIgM-FISH, the incidence of 6q- was higher (54%). Interestingly, 6q- patients displayed features associated with adverse prognosis (higher levels of ESR, CRP and beta-2 microglobulin), and a greater tendency to display anemia and hypoalbuminemia. Other differentiating variables without reaching statistical significance were a tendency of displaying a higher bone marrow lymphoplasmacytoid infiltration and the amount of monoclonal component in 6q- patients (table). In addition, patients with 6q- displayed shorter survival from time of diagnose (log-rank; p=0.09). In summary, our results show that 6q deletion in WM patients is currently the most frequently found cytogenetic abnormality. Patients with this deletion also shows a trend towards an aggressive disease and poorer outcome in WM. Further studies should focus on possible tumor suppressor genes in the minimal area of deletion at 6q and to determine their role in disease progression. table del6q present del6q absent p-value n 40 (39%) 62 (61%) β2M ≥4mg/dL 48% 16% 0.005 CRP ≥3.5 mg/dL 47% 11% 0.006 Albumin <4mg/dL 86% 55% 0.006 ESR ≥100 mm/h 73% 44% 0.02 Hb <11 g/dL 63% 40% 0.02 serum IgM >20 g/L 86% 73% 0.10 BM infiltration >40% 44% 31% 0.20

Abstract Background: B-chronic lymphocytic leukemia (B-CLL) is the most common leukemia in the Western world but its pathogenesis remains largely unknown. Our strategy was to employ gene expression profiling (GEP) to discover genetic differences between CLL B cells and blood B cells from healthy adults. Previously, we and others identified the transcription factor (TF) lymphocyte enhancer factor-1 (LEF-1) as one of several genes significantly over expressed in CLL B cells suggesting a role for the oncogenic Wnt signaling pathway. LEF-1 acts as a central mediator of Wnt signaling and is crucial for the proliferation and survival of pro-B cells during development. Recently, deregulated LEF-1 activation has been directly linked with leukemogenesis. Methodology: The goals of our study were to: validate LEF-1 over expression in CLL B cells in a new cohort of B-CLL patients and normal controls; study CLL B cell LEF-1 protein expression; and investigate CLL B cell expression levels of other genes linked to Wnt signaling. To accomplish these goals, Affymetrix U133 GEP was performed on B cells from 41 B-CLL patients who were enrolled on a trial of combined pentostatin, cyclophosphamide, and rituximab and 11 healthy adults over age 60. Only the perfect match data were utilized for all analyses; the non-background corrected perfect match data were normalized using an intensity-dependent procedure and analyses were done using the base-2 logarithm transformed normalized values. Results: GEP analysis confirmed CLL B cells expressed the LEF-1 gene at ~28-fold higher levels than normal B cells (p<.0001). These results were validated by quantitative PCR and all CLL B cells studied expressed LEF-1 mRNA. By contrast, LEF-1 mRNA expression was undetectable in blood B cells from healthy adults both before and after in vitro mitogenic stimulation suggesting aberrant LEF-1 expression in B-CLL. Moreover, LEF-1 protein was readily detected by flow cytometry in CLL B cell samples and all clonal B cells expressed a uniform level of LEF-1. Full length LEF-1 is more oncogenic and predominates in certain cancers, while a dominant negative short isoform is found at greater levels in normal lymphocytes. Of interest, western blot analysis revealed that CLL B cells predominantly expressed full length oncogenic LEF-1. Ongoing studies are focused on silencing LEF-1 expression to determine LEF-1 target genes. In this regard, IGFBP4 (IGF binding protein 4) mRNA expression levels are 19-fold higher in CLL vs control B cells (p<0.0001) and the IGFBP4 protein was recently shown to antagonize Wnt signaling. A scan of the IGFBP4 promoter element identified 3 possible LEF/TCF consensus sites. Thus, there is a possible negative feedback loop in CLL, with activation of the Wnt pathway leading to expression of a negative Wnt regulator. Finally, we queried the GEP data for evidence of differential expression of 63 other Wnt-related genes. Surprisingly, in addition to LEF1, only five genes met our selection threshold of ≥1.5 fold change in expression between CLL and control B cells and p value <.001. These genes were CSNK1D (casein kinase, delta 1; 1.9-fold higher in control vs CLL; p<0.0001); CCND2 (cyclin D2; 2.4-fold higher in CLL vs control; p<0.0001); JUN (3.2-fold higher in control vs CLL); WNT3 (6.4-fold higher in CLL vs control; p<0.0001); and TCF4 (transcription factor 4, alias ITF-2; 4-fold higher in CLL vs control; p<0.0001). To our knowledge, we are the first to report that the TCF4 (ITF-2) gene is over expressed in B-CLL. This TF is of great interest because it is a known downstream target of the Wnt/TCF pathway, is activated in human cancers with b-catenin defects, and it promotes neoplastic transformation. Using Spearman correlation analysis to explore the relationship between LEF1, TCF4, and WNT3 expression levels, we observed a marginal correlation between WNT3 expression and LEF1 (ρ=0.31; p value=0.05) and TCF4 (ρ=0.29; p value=0.07). Summary: These studies add new support for a critical role of the Wnt pathway in CLL. The WNT3 results are consistent with the literature; however, it is notable that we failed to corroborate other reports demonstrating that other Wnts and Fzd genes are differentially expressed in CLL B cells vs normal B cells. It is striking that CLL B cells over express two TFs in this pathway that have been linked with neoplastic transformation. Ongoing studies are aimed at further elucidating the roles of these genes in B-CLL.

Coronavirus disease 2019 (COVID-19) is a global pandemic that is wreaking havoc on the health and economy of much of human civilization. Electrophysiologists have been impacted personally and professionally by this global catastrophe. In this joint article from representatives of the Heart Rhythm Society, the American College of Cardiology, and the American Heart Association, we identify the potential risks of exposure to patients, allied healthcare staff, industry representatives, and hospital administrators. We also describe the impact of COVID-19 on cardiac arrhythmias and methods of triage based on acuity and patient comorbidities. We provide guidance for managing invasive and noninvasive electrophysiology procedures, clinic visits, and cardiac device interrogations. In addition, we discuss resource conservation and the role of telemedicine in remote patient care along with management strategies for affected patients.

INTRODUCTION The cerebral cortex underlies our complex cognitive capabilities. Variations in human cortical surface area and thickness are associated with neurological, psychological, and behavioral traits and can be measured in vivo by magnetic resonance imaging (MRI). Studies in model organisms have identified genes that influence cortical structure, but little is known about common genetic variants that affect human cortical structure. RATIONALE To identify genetic variants associated with human cortical structure at both global and regional levels, we conducted a genome-wide association meta-analysis of brain MRI data from 51,665 individuals across 60 cohorts. We analyzed the surface area and average thickness of the whole cortex and 34 cortical regions with known functional specializations. RESULTS We identified 369 nominally genome-wide significant loci ( P < 5 × 10 −8 ) associated with cortical structure in a discovery sample of 33,992 participants of European ancestry. Of the 360 loci for which replication data were available, 241 loci influencing surface area and 66 influencing thickness remained significant after replication, with 237 loci passing multiple testing correction ( P < 8.3 × 10 −10 ; 187 influencing surface area and 50 influencing thickness). Common genetic variants explained 34% (SE = 3%) of the variation in total surface area and 26% (SE = 2%) in average thickness; surface area and thickness showed a negative genetic correlation ( r G = −0.32, SE = 0.05, P = 6.5 × 10 −12 ), which suggests that genetic influences have opposing effects on surface area and thickness. Bioinformatic analyses showed that total surface area is influenced by genetic variants that alter gene regulatory activity in neural progenitor cells during fetal development. By contrast, average thickness is influenced by active regulatory elements in adult brain samples, which may reflect processes that occur after mid-fetal development, such as myelination, branching, or pruning. When considered together, these results support the radial unit hypothesis that different developmental mechanisms promote surface area expansion and increases in thickness. To identify specific genetic influences on individual cortical regions, we controlled for global measures (total surface area or average thickness) in the regional analyses. After multiple testing correction, we identified 175 loci that influence regional surface area and 46 that influence regional thickness. Loci that affect regional surface area cluster near genes involved in the Wnt signaling pathway, which is known to influence areal identity. We observed significant positive genetic correlations and evidence of bidirectional causation of total surface area with both general cognitive functioning and educational attainment. We found additional positive genetic correlations between total surface area and Parkinson’s disease but did not find evidence of causation. Negative genetic correlations were evident between total surface area and insomnia, attention deficit hyperactivity disorder, depressive symptoms, major depressive disorder, and neuroticism. CONCLUSION This large-scale collaborative work enhances our understanding of the genetic architecture of the human cerebral cortex and its regional patterning. The highly polygenic architecture of the cortex suggests that distinct genes are involved in the development of specific cortical areas. Moreover, we find evidence that brain structure is a key phenotype along the causal pathway that leads from genetic variation to differences in general cognitive function. Identifying genetic influences on human cortical structure. ( A ) Measurement of cortical surface area and thickness from MRI. ( B ) Genomic locations of common genetic variants that influence global and regional cortical structure. ( C ) Our results support the radial unit hypothesis that the expansion of cortical surface area is driven by proliferating neural progenitor cells. ( D ) Cortical surface area shows genetic correlation with psychiatric and cognitive traits. Error bars indicate SE. IMAGE CREDITS: (A) K. COURTNEY; (C) M. R. GLASS

8522 Background: CC-223 is an ATP-competitive inhibitor of the mTOR kinase, including both TORC1 and TORC2 complexes. CC-223 was selected to address resistance of rapamycin analogues mediated by TORC2 activation. Methods: Following establishment of the MTD (reported at ASCO 2012), subjects with advanced DLBCL, MM and select solid tumors were enrolled in parallel expansion cohorts of up to 20 evaluable subjects. CC-223 was dosed at 45 mg once daily in 28 day cycles until disease progression. Results: As of 09 January, 2013, 35 subjects were enrolled including DLBCL (21) and MM (14). Results in solid tumor cohorts are reported separately. The most common (> 20%) related adverse events (all grades) were fatigue, hyperglycemia, rash, anorexia, nausea, vomiting and diarrhea. In addition, related serious adverse events included infection (2), pneumonitis (1), renal insufficiency (2), pancreatitis (1) and thrombocytopenia (1). CC-223 dose reduction was required in 9 subjects (27%), usually during cycle 1 or 2, and 4 additional subjects with DLBCL dropped out during cycle 1 due to toxicity. Systemic exposure was similar between the two tumor cohorts and was associated with inhibition of TORC1 (p4EBP1) and TORC2 (pAKT) biomarkers in blood cells. Reduction in glucose uptake (32 – 98% decrease) on PET imaging at day 15 was observed in 7/7 DLBCL subjects with results currently available. Three of 17 evaluable subjects with DLBCL had partial responses (PR) after 2 cycles; two with rapid and near complete regression (> 90%) of target lesions by CT and PET with PR confirmed and treatment ongoing at 6 and 8 cycles. Both had failed multiple prior treatment regimens (5 and 3, respectively), including autologous stem cell transplant (ASCT). No responses were observed in 10/14 evaluable subjects with MM although 2 subjects have prolonged stable disease (SD) with treatment ongoing at 12 and 14 cycles. Conclusions: Encouraging signals of biomarker and clinical activity were observed in DLBCL, including two near complete responses, which are ongoing. Due to dose reductions and interruptions, a starting dose of 30 mg QD is recommended for future studies. Clinical trial information: NCT01177397.

TPS3113 Background: Programmed death-1 (PD-1) is an immune checkpoint receptor that inhibits T-cell activation upon interaction with its ligands PD-L1 or PD-L2. Increased PD-L1 expression has been reported with various hematologic malignancies and may prevent the host immune response from exerting an antitumor effect on the malignant cells. Nivolumab, a fully human IgG4 monoclonal PD-1 receptor blocking antibody, has demonstrated antitumor activity in pts with solid tumors including melanoma, renal cell carcinoma, and non-small cell lung carcinoma. We hypothesized that nivolumab could also mediate antitumor activity in pts with hematologic malignancies, a significant area of unmet medical need. We describe a phase I study to evaluate the effects of nivolumab in pts with select hematologic malignancies. Methods: This open-label, two-part study will enroll approximately 100 pts. During dose escalation, successive cohorts of pts with relapsed or refractory hematologic malignancies will be treated using a 6+3 escalation design. Pts will receive 1 or 3 mg/kg nivolumab IV every 2 weeks (wks) (the first dose will be followed by a 3-wk evaluation period), for 2 years, with the potential for an additional year of therapy for pts who progress during the follow-up period. Subsequently, 5 tumor-specific cohorts of 16 pts will be enrolled at the maximum tolerated dose (MTD) for multiple myeloma, B-cell lymphoma, T-cell lymphoma, Hodgkin lymphoma/primary mediastinal B-cell lymphoma, and chronic myelogenous leukemia. Response will be assessed at wks 4, 8, 16, 24, and every 16 wks thereafter. The primary study objective is to establish dose limiting toxicities, the MTD, and the recommended phase II nivolumab dose. Secondary objectives are to characterize nivolumab pharmacokinetics, immunogenicity, preliminary antitumor activity, and the potential association between PD-L1 expression on tumor cells and clinical efficacy. Exploratory objectives include investigation of the immunoregulatory effects of nivolumab in peripheral blood, bone marrow, and/or tumor. Pts are currently being enrolled at 3 mg/kg. Clinical trial information: NCT01592370.

Introduction . The triglyceride and glucose (TyG) index has been described as a biochemical marker of insulin resistance (IR); however, its diagnostic accuracy remains uncertain. Objective . To summarize the evidence assessing the diagnostic accuracy of the TyG index regarding IR. Methods . A comprehensive search in MEDLINE, EMBASE, Web of Science, and Scopus was performed without any language restriction. Studies assessing the diagnostic accuracy of the TyG index against the hyperinsulinemic-euglycemic clamp (HIEC) or any other IR biochemical were assessed independently and in duplicate. Diagnostic accuracy measures (sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratios) were extracted independently and in duplicate. The QUADAS-2 tool was used to assess the risk of bias of independent studies. Results . We identified 15 eligible studies with 69,922 participants and an overall quality of low to moderate. The TyG index was evaluated by HIEC and HOMA as reference tests. The highest achieved sensitivity was 96% using HIEC, and the highest specificity was of 99% using HOMA-IR, with a cutoff value of 4.68. AUC values varied from 0.59 to 0.88. Cutoff values for IR were variable between studies, limiting its comparability. Conclusion . In this systematic review, we found moderate-to-low quality evidence about the usefulness of the TyG index as a surrogate biochemical marker of IR. Due to the lack of a standardized IR definition and heterogeneity between studies, further validation and standardized cutoff values are needed to be used in clinical practice.