Impact of Carbamide Peroxide Whitening Agent on Dentinal Collagen

Carbamide peroxide (CP) is widely used as a tooth-whitening agent in self-administered tooth-bleaching products. In this study, the effects of 5% and 10% CP on dentinal collagen structure and chemical properties were evaluated in vitro. Thirty-five intact teeth were exposed to 2 whitening protocols (2 or 4 h daily) with either 5% or 10% CP gel for 1 wk. Shade changes before and after the whitening protocol were captured colorimetrically using a spectroshade. Collagen scaffold models and demineralized dentine disc samples were prepared and exposed to CP droplets (5% or 10%). Structural changes were investigated using electron microscopy. Finally, mineralized dentine disc samples were prepared postbleaching to assess chemical changes resulting from CP exposure in dentinal collagen using Raman spectroscopy. Results showed a difference in tooth shade when exposed to 5% and 10% CP whitening protocols, with a significantly ( P ≤ 0.01) greater change reported for the 10% CP/4-h group. Imaging of the collagen scaffold model following exposure to CP showed a gelatinization process indicating that the free radical by-products from CP are able to disrupt the quaternary structure of noncrosslinked collagen. The most significant damage on the collagen scaffold was seen for the 10% CP exposure for 4 h. Imaging of the demineralized discs displayed the same glassy amorphous layer appearance as found in the collagen scaffold. Raman spectra of the mineralized dentine discs showed a significant decrease ( P ≤ 0.01) in the integrated area of amide I and amide III values in the 4 test groups following CP application. Amide I was more affected as both the exposure time and concentration of CP increased. Despite the claimed safety of whitening agents, this in vitro study concludes that even low concentrations of CP result in a deleterious change in dentinal collagen.

Future Directions in Research and Intervention with Youths in Poverty

This article aims to integrate theory and empirical findings about understanding and fostering the process of resilience and adaptation in children and families who live in poverty. In this article, we draw from multiple, somewhat distinct, scholarly streams to identify sources of protection, integrating across the literatures on stress and coping, psychophysiology, cultural identity development, and empowerment theory. Because living in poverty cuts across other dimensions of social differentiation and structural inequality, intersectionality theory frames our discussion of how to leverage poverty-affected youths' diverse experiences. We present a framework to guide intervention and research on resiliency promotion, describe the Building a Strong Identity and Coping Skills intervention stemming from the framework, and suggest possible avenues and next steps for both interventions and research.

Early barriers to neonatal porcine islet engraftment in a dual transplant model

Porcine islet xenografts have the potential to provide an inexhaustible source of islets for β cell replacement. Proof-of-concept has been established in nonhuman primates. However, significant barriers to xenoislet transplantation remain, including the poorly understood instant blood-mediated inflammatory reaction and a thorough understanding of early xeno-specific immune responses. A paucity of data exist comparing xeno-specific immune responses with alloislet (AI) responses in primates. We recently developed a dual islet transplant model, which enables direct histologic comparison of early engraftment immunobiology. In this study, we investigate early immune responses to neonatal porcine islet (NPI) xenografts compared with rhesus islet allografts at 1 hour, 24 hours, and 7 days. Within the first 24 hours after intraportal infusion, we identified greater apoptosis (caspase 3 activity and TUNEL [terminal deoxynucleotidyl transferase dUTP nick end labeling])-positive cells) of NPIs compared with AIs. Macrophage infiltration was significantly greater at 24 hours compared with 1 hour in both NPI (wild-type) and AIs. At 7 days, IgM and macrophages were highly specific for NPIs (α1,3-galactosyltransferase knockout) compared with AIs. These findings demonstrate an augmented macrophage and antibody response toward xenografts compared with allografts. These data may inform future immune or genetic manipulations required to improve xenoislet engraftment.

Abstract P2-03-08: A retrospective study to identify the frequency of discordant HER2 results using both immunohistochemistry (IHC) and in-situ hybridization (ISH) assays

Background

HER2 targeted therapies have substantially improved survival outcomes for patients with breast cancer and HER2 amplification of their tumour. The recently updated American Society of Clinical Oncology/College of American Pathologists (ASCO CAP) guidelines recommend that HER2 testing to be performed on all invasive breast cancers and that positive HER2 status is defined by either evidence of HER2 protein over-expression measured by immunohistochemistry status (IHC 3+) or by in-situ hybridisation (ISH) amplification. Equivocal results require further testing with the alternative assay.

In Australia, Medicare-funded access to HER2 targeted therapies requires demonstration of HER2 positivity by ISH, regardless of IHC status. Thus, currently most breast units perform IHC and ISH on all breast cancers. Given this discrepancy in practice and significant additional cost of performing ISH, this study evaluated the frequency of discordance and the cost burden in using both assays in a historical series of patients with breast cancer.

Methods

A retrospective audit of HER2 histopathology reports was performed for all breast cancers diagnosed between 2007 and 2016 at a single tertiary hospital in Melbourne, Australia (The Austin Hospital). HER2 IHC results were classified as negative (0 or 1+), equivocal (2+) or positive (3+). An analysis was performed to assess the proportion of concordant (defined as samples with IHC 0/1+ and negative ISH, samples with IHC3+ and positive ISH, and samples with IHC2+ regardless of ISH) and discordant results (defined as IHC 3+ and ISH non-amplified or IHC 0/1+ and ISH amplified). Tumour blocks and slides from discordant cases were reviewed by a breast cancer histopathologist. The cost of additional testing in concordant cases was performed based on the Australian Medicare Benefits Schedule (MBS).

Results

Eight hundred and forty-six histopathology reports were reviewed from 786 patients, all of whom had both IHC and ISH assays. There were 832 (98.8%) concordant cases. There were 10 discordant cases (1.2%) in total, including three cases (0.4%) with a negative IHC (1+) result but positive ISH, and 7 cases (0.8%) with a positive IHC but negative ISH result. A detailed analysis of 10 discordant cases will be presented. HER2 status and subsequent treatment remain unchanged with the addition of ISH testing in 665 (79.0%) cases, which amounted to an additional $209,741 (AUD) being spent on unnecessary ISH testing. Given an estimated incidence of 17,730 new cases of breast cancer per year in Australia, the population cost of performing additional HER2 ISH testing ($315.40 per case) in concordant cases would equate to $4.4 million (AUD) per year.

Conclusion

These results describe an extremely low rate of HER2 IHC/ISH discordance suggesting that routine use of both assays is unnecessary in cases with an unequivocal IHC result. The fiscal burden and potential delays to deciding treatment provide a strong rationale for access to HER2 targeted therapies to be based IHC or ISH, as advised by the ASCO CAP guidelines. Our results will be used to support a national review of IHC and ISH discordance using Australian national registry data.

Citation Format: Balasubramanian A, Ireland-Jenkin K, McDonald A, Khor R, Yeo B, Leong T. A retrospective study to identify the frequency of discordant HER2 results using both immunohistochemistry (IHC) and in-situ hybridization (ISH) assays [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-03-08.

Abstract P2-09-30: A gene expression signature that predicts for trastuzumab response in HER2+ breast cancer

Background: Approximately 15-20% of breast cancers overexpress HER2. These patients are eligible for trastuzumab in combination with chemotherapy. However, some patients are extreme responders to single agent trastuzumab and we wanted to identify differences in cancer gene expression that could predict response to single agent trastuzumab.

Methods: We performed paired-end RNAseq on an isogenic cellular model of trastuzumab sensitivity and resistance. We reasoned that the isogenic nature of the cellular clones used in this study would enrich for differentially-expressed genes (DEGs) that were associated with response to single-agent trastuzumab. DEGs where chosen based upon either i) large fold changes in resistant vs. sensitive clones, ii) high frequency in human HER2+ breast cancers, or iii) were found to be enriched with other DEGs in signaling pathways selected by Ingenuity Pathway Analysis (IPA). DEGs were further scrutinized based upon associations with overall survival (OS) in HER2+ human breast cancers. The resulting genes were validated using qPCR and in several independent sample sets containing gene expression profiles of human breast cancers.

Results: Discovery: RNAseq yielded 3,241 statistically-significant DEGs. We used two independent filtering pipelines to obtain 175 DEGs. Ingenuity Pathway Analysis found signaling pathways associated with eukaryotic initiation factor, lysine specific demethylase 5B, and estrogen receptor alpha to be enriched in DEGs associated with trastuzumab resistance. Of these DEGs, six genes correlated with a statistically significant change in OS in the training dataset, and were validated by qPCR in the cell lines used for the analysis. We further determined that the six-gene signature was a negative predictor of overall survival in HER2+ breast cancer patients whose cancers carried at least one DEG. Validation: Using independent cohorts from TCGA and the website KMplot.com, we validated the predictive power of the six-gene signature. Of the 47 HER2+ patients from TCGA, eight patients carried two more DEGs, while 39 carried ≤ 1 DEG. Although the numbers are small, of the 8 patients followed for four or more years, only one patient was alive as compared with 7 out of 39 patients without the signature. Similarly, Kaplan Meier analysis of gene expression data from KMplot.com revealed that only 1 out of 23 patients (4.3%) who carried high mean expression of the six-gene signature were free of distant metastases after 87 months, compared to 4 out of 43 patients (9.3%) from the cohort carrying low mean expression of the six-gene signature. In both validation cohorts, the six DEG signature was not predictive in HER2-negative breast cancers.

Discussion: Patients whose tumors lack this gene expression signature are more likely to experience a favorable response to trastuzumab therapy. This signature requires validation in a clinical cohort treated with trastuzumab monotherapy.

Citation Format: Abukhdeir AM, Najor MS, Turturro SB, Armstrong AR, McDonald A, Fogg L, Cobleigh MA. A gene expression signature that predicts for trastuzumab response in HER2+ breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-09-30.

An evaluative tool for rapid assessment of derelict vessel effects on coastal resources

Derelict vessels impact coastal and estuarine habitats, fisheries resources, are aesthetically unappealing, and may be a hazard to navigation and recreation. The Government Accountability Office estimated in 2013 over 5600 derelict vessels existed throughout the coastal United States. Considering the large number of derelict vessels present in coastal areas, effective tools are needed to assess the environmental damage exerted by derelict vessels and aid in management strategies for their removal. After carefully reviewing regulations, we developed a 100-point scoring rubric (DVET) to evaluate damage by derelict vessels to natural resources with minimal field effort. The DVET's ability to rapidly assess a derelict vessel's impact on surrounding natural resources was confirmed with additional rigorous sampling and suggest environmental enhancement following vessel removal. The DVET shows promise for informing derelict vessel removal strategies, although more work is needed to quantify environmental benefits of derelict vessel removal and establish guidelines for removal prioritization.

Assessing soil properties and nutrient availability under conservation agriculture practices in a reclaimed sodic soil in cereal-based systems of North-West India

Soil quality degradation associated with resources scarcity is the major concern for the sustainability of conventional rice-wheat system in South Asia. Replacement of conventional management practices with conservation agriculture (CA) is required to improve soil quality. A field experiment was conducted to assess the effect of CA on soil physical (bulk density, penetration resistance, infiltration) and chemical (N, P, K, S, micronutrients) properties after 4 years in North-West India. There were four scenarios (Sc) namely conventional rice-wheat cropping system (Sc1); partial CA-based rice-wheat-mungbean system (RWMS) (Sc2); CA-based RWMS (Sc3); and CA-based maize-wheat-mungbean (Sc4) system. Sc2 (1.52 Mg m^-3) showed significantly lower soil bulk density (BD). In Sc3 and Sc4, soil penetration resistance (SPR) was reduced and infiltration was improved compared to Sc1. Soil organic C was significantly higher in Sc4 than Sc1. Available N was 33% and 68% higher at 0-15 cm depth in Sc3 and Sc4, respectively, than Sc1. DTPA extractable Zn and Mn were significantly higher under Sc3 and Sc4 compared to Sc1. Omission study showed 30% saving in N and 50% in K in wheat after four years. Therefore, CA improved soil properties and nutrient availability and have potential to reduce external fertilizer inputs in long run.

Carbon dating cancer: defining the chronology of metastatic progression in colorectal cancer

Background

Patients often ask oncologists how long a cancer has been present before causing symptoms or spreading to other organs. The evolutionary trajectory of cancers can be defined using phylogenetic approaches but lack of chronological references makes dating the exact onset of tumours very challenging.

Patients and methods

Here, we describe the case of a colorectal cancer (CRC) patient presenting with synchronous lung metastasis and metachronous thyroid, chest wall and urinary tract metastases over the course of 5 years. The chest wall metastasis was caused by needle tract seeding, implying a known time of onset. Using whole genome sequencing data from primary and metastatic sites we inferred the complete chronology of the cancer by exploiting the time of needle tract seeding as an in vivo 'stopwatch'. This approach allowed us to follow the progression of the disease back in time, dating each ancestral node of the phylogenetic tree in the past history of the tumour. We used a Bayesian phylogenomic approach, which accounts for possible dynamic changes in mutational rate, to reconstruct the phylogenetic tree and effectively 'carbon date' the malignant progression.

Results

The primary colon cancer emerged between 5 and 8 years before the clinical diagnosis. The primary tumour metastasized to the lung and the thyroid within a year from its onset. The thyroid lesion presented as a tumour-to-tumour deposit within a benign Hurthle adenoma. Despite rapid metastatic progression from the primary tumour, the patient showed an indolent disease course. Primary cancer and metastases were microsatellite stable and displayed low chromosomal instability. Neo-antigen analysis suggested minimal immunogenicity.

Conclusion

Our data provide the first in vivo experimental evidence documenting the timing of metastatic progression in CRC and suggest that genomic instability might be more important than the metastatic potential of the primary cancer in dictating CRC fate.

Long-term results and recurrence patterns from SCALOP: a phase II randomised trial of gemcitabine- or capecitabine-based chemoradiation for locally advanced pancreatic cancer

BACKGROUND

SCALOP, a randomised, phase II trial, tested the activity and safety of gemcitabine (GEM)-based and capecitabine (CAP)-based chemoradiation (CRT) for locally advanced pancreatic cancer (LAPC). Here we present the long-term outcomes.

METHODS

Eligibility: histologically proven LAPC ⩽7 cm. Following 12 weeks of induction GEMCAP chemotherapy (three cycles: GEM 1000 mg m-2 days 1, 8, 15; CAP 830 mg m-2 days 1-21 q28 days) patients with stable/responding disease, tumour ⩽6 cm, and WHO Performance Status 0-1 were randomised to receive one cycle GEMCAP followed by CAP (830 mg m-2 b.d. on weekdays only) or GEM (300 mg m-2 weekly) with radiation (50.4 Gy per 28 fractions).

RESULTS

One-hundred fourteen patients (28 UK centres) were registered between 24 December 2009 and 25 October 2011, and 74 were randomised (CAP-RT=36; GEM-RT=38). At the time of this analysis, 105 of the 114 patients had died and the surviving 9 patients had been followed up for a median of 10.9 months (IQR: 2.9-18.7). Updated median OS was 17.6 months (95% CI: 14.6-22.7) in the CAP-CRT arm and 14.6 months (95% CI: 11.1-16.0) in the GEM-CRT arm (intention-to-treat adjusted hazard ratio (HR): 0.68 (95% CI: 0.38-1.21, P=0.185)); median progression-free survival (PFS) was 12.0 months (95% CI: 10.0-15.2) in the CAP-CRT arm and 10.4 months (95% CI: 8.8-12.7) in the GEM-CRT arm (intention-to-treat adjusted HR: 0.60 (95% CI: 0.32-1.14, P=0.120)). In baseline multivariable model, age ⩾65 years, better performance status, CA19.9<613 IU l-1, and shorter tumour diameter predicted improved OS. CAP-CRT, age ⩾65 years, better performance status, CA19.9 <46 IU ml-1 predicted improved OS and PFS in the pre-radiotherapy model. Nine-month PFS was highly predictive of OS.

CONCLUSIONS

CAP-CRT remains the superior regimen. SCALOP showed that patients with CA19.9 <46 IU ml-1 after induction chemotherapy are more likely to benefit from CRT.

Runx1 Orchestrates Sphingolipid Metabolism and Glucocorticoid Resistance in Lymphomagenesis

The three‐membered RUNX gene family includes RUNX1, a major mutational target in human leukemias, and displays hallmarks of both tumor suppressors and oncogenes. In mouse models, the Runx genes appear to act as conditional oncogenes, as ectopic expression is growth suppressive in normal cells but drives lymphoma development potently when combined with over‐expressed Myc or loss of p53. Clues to underlying mechanisms emerged previously from murine fibroblasts where ectopic expression of any of the Runx genes promotes survival through direct and indirect regulation of key enzymes in sphingolipid metabolism associated with a shift in the “sphingolipid rheostat” from ceramide to sphingosine‐1‐phosphate (S1P). Testing of this relationship in lymphoma cells was therefore a high priority. We find that ectopic expression of Runx1 in lymphoma cells consistently perturbs the sphingolipid rheostat, whereas an essential physiological role for Runx1 is revealed by reduced S1P levels in normal spleen after partial Cre‐mediated excision. Furthermore, we show that ectopic Runx1 expression confers increased resistance of lymphoma cells to glucocorticoid‐mediated apoptosis, and elucidate the mechanism of cross‐talk between glucocorticoid and sphingolipid metabolism through Sgpp1. Dexamethasone potently induces expression of Sgpp1 in T‐lymphoma cells and drives cell death which is reduced by partial knockdown of Sgpp1 with shRNA or direct transcriptional repression of Sgpp1 by ectopic Runx1. Together these data show that Runx1 plays a role in regulating the sphingolipid rheostat in normal development and that perturbation of this cell fate regulator contributes to Runx‐driven lymphomagenesis. J. Cell. Biochem. 118: 1432–1441, 2017. © 2016 The Authors. Journal of Cellular Biochemistry Published by Wiley Periodicals, Inc.