SMARCD1 is a "Goldilocks" metastasis modifier

Breast cancer is the most frequently diagnosed cancer worldwide, constituting around 15% of all diagnosed cancers in 2023. The predominant cause of breast cancer-related mortality is metastasis to distant essential organs, and a lack of metastasis-targeted therapies perpetuates dismal outcomes for late-stage patients. However, through our use of meiotic genetics to study inherited transcriptional network regulation, we have identified a new class of "Goldilocks" genes that are promising candidates for the development of metastasis-targeted therapeutics. Building upon previous work that implicated the CCR4-NOT RNA deadenylase complex in metastasis, we now demonstrate that the RNA-binding proteins (RNA-BPs) NANOS1, PUM2, and CPSF4 also regulate metastatic potential. Using cell lines, 3D culture, mouse models, and clinical data, we pinpoint Smarcd1 mRNA as a key target of all three RNA-BPs. Strikingly, both high and low expression of Smarcd1 is associated with positive clinical outcomes, while intermediate expression significantly reduces the probability of survival. Applying the theory of "essential genes" from evolution, we identify an additional 50 genes that span several cellular processes and must be maintained within a discrete window of expression for metastasis to occur. In the case of Smarcd1, small perturbations in its expression level significantly reduce metastasis in laboratory mouse models and alter splicing programs relevant to the ER+/HER2-enriched breast cancer subtype. The identification of subtype-specific "Goldilocks" metastasis modifier genes introduces a new class of genes and potential catalogue of novel targets that, when therapeutically "nudged" in either direction, may significantly improve late-stage patient outcomes.

Leave events among Aboriginal and Torres Strait Islander people: a systematic review

BACKGROUND

Leave events are a public health concern resulting in poorer health outcomes. In Australia, leave events disproportionally impact Aboriginal and Torres Strait Islander people. A systematic review was conducted to explore the causes of leave events among Aboriginal and Torres Strait Islander people and strategies to reduce them.

METHODS

A systematic review was conducted using Medline, Web of Science, Embase and Informit, a database with a strong focus on relevant Australian content. Additionally, we examined the references of the records included, and performed a manual search using Google, Google scholar and the Australia's National Institute for Aboriginal and Torres Strait Islander Health Research. Two independent reviewers screened the records. One author extracted the data and a second author reviewed it. To appraise the quality of the studies the Mixed Methods Appraisal Tool was used as well as the Aboriginal and Torres Strait Islander Quality Appraisal Tool. A narrative synthesis was used to report quantitative findings and an inductive thematic analysis for qualitative studies and reports.

RESULTS

We located 421 records. Ten records met eligibility criteria and were included in the systematic review. From those, four were quantitative studies, three were qualitative studies and three reports. Five records studied data from the Northern Territory, two from Western Australia, two from New South Whales and one from Queensland. The quantitative studies focused on the characteristics of the patients and found associations between leave events and male gender, age younger than 45 years and town camp residency. Qualitative findings yielded more in depth causes of leave events evidencing that they are associated with health care quality gaps. There were multiple strategies suggested to reduce leave events through adapting health care service delivery. Aboriginal and Torres Strait Islander representation is needed in a variety of roles within health care provision and during decision-making.

CONCLUSION

This systematic review found that multiple gaps within Australian health care delivery are associated with leave events among Aboriginal and Torres Strait Islander people. The findings suggest that reducing leave events requires better representation of Aboriginal and Torres Strait Islander people within the health workforce. In addition, partnership with Aboriginal and Torres Strait Islander people is needed during the decision-making process in providing health services that meet Aboriginal and Torres Strait Islander cultural needs.

Non-fatal injuries among boys and girls presenting to Red Cross War Memorial Children's Hospital, Cape Town, South Africa

BACKGROUND

In South Africa (SA), road traffic injuries, homicides and burns are the leading causes of injury-related deaths among children. Injury-related deaths are well documented for SA, but this is not the case for non-fatal injuries.

OBJECTIVES

To describe the non-fatal injuries sustained among children aged 0 - 13 years, to identify any significant sex differences by age group, cause of injury, admission status and injury severity.

METHODS

The trauma unit database from 1997 to 2016 at Red Cross War Memorial Children's Hospital, Cape Town, was utilised for this analysis. The prevalence of injuries and the boy/girl ratios with 95% confidence intervals (CIs) were reported.

RESULTS

Analysis indicated significant differences by sex for individual injury causes (transport, assault, burns, falls and other injuries), age group, injury severity and admission status. Moderately severe injuries were largely caused by burns, while severe injuries were mostly transport related. Boys had significantly higher proportions of all injury causes. The boy/girl ratio was lowest for assault (1:18), where significantly more girls aged 1 - 3 and 4 - 6 years were injured. Rape/sexual assault was 5.5 times higher for girls, with a significantly higher proportion of moderate-severity injuries (87%; 95% CI 84.7 - 89.4).

CONCLUSION

The study findings call for a more targeted prevention response for boy and girl children. Interventions should be targeted at the prevention of burns, traffic collisions and interpersonal violence, in particular sexual assaults against girls.

A modified Dabestani-Mahan formula estimates a normal pulmonary artery systolic pressure: a single-center retrospective study

Background

Pulmonary artery systolic pressure (PASP) is increasingly used as an important datapoint in clinical decision-making and prognostication even in specialties outside of cardiology. Estimation of PASP by Doppler quantification using tricuspid regurgitation (TR) peak velocity is commonly used and correlates well with invasive measurement by right heart catheterization. Further study of transthoracic echocardiogram (TTE) techniques to estimate PASP is needed to provide this datapoint in the absence of sufficient Doppler data for the TR peak velocity method. One technique using right ventricular outflow tract acceleration time (AT) to estimate mean pulmonary artery pressure (MPAP) has been proposed by Dabestani Et al. by the equation MPAP=90-(0.62x AT). Assuming a linear relationship between MPAP and PASP, as suggested by Chemla Et al. by MPAP=(0.61xPASP)+2, a modified formula PASP=145-AT could possibly estimate a normal PASP ≤25 mmHg.

Purpose

To examine if a modified Dabestani-Mahan formula PASP=145-AT can estimate a normal PASP ≤25 mmHg as calculated by the TR peak velocity method.

Methods

We queried the electronic medical record at our institution for a sample of 300 patients who had a TTE performed between 2017 and 2020. Each TTE was reviewed and PASP was estimated for each using the TR peak velocity method. A right atrial pressure of 3 mmHg, 8 mmHg, or 15 mmHg was used in the estimation based on inferior vena cava diameter and collapsibility in keeping with the 2015 American Society of Echocardiography guidelines. A short axis view of pulmonary flow using the pulse-waved Doppler sample volume over the transpulmonary valve jet was then reviewed. The time from onset of ejection to peak flow velocity was measured manually as AT in milliseconds using Change Healthcare Cardiology Web Software Package 14.1.1. The measured AT was averaged over three cardiac cycles. Patients with a heart rate between 60 and 100 beats per minute at time of TTE and with sufficient Doppler data to estimate PASP by TR peak velocity and to measure AT were included in a logistic regression analysis.

Results

154 patients were included in the statistical analysis. Patients who had a right ventricular outflow tract acceleration time greater than 120 milliseconds, giving a PASP ≤25 mmHg by the modified formula PASP=145-AT, had a 36 times greater odds of having a PASP ≤25 mmHg by the TR peak velocity method (OR=36.0, 95% CI=10.36–125.12, p<0.001).

Conclusion(s)

Based on a single-center sample, a right ventricular outflow tract acceleration time greater than 120 milliseconds could be used to estimate a normal pulmonary artery systolic pressure less than or equal to 25 mmHg in the absence of sufficient Doppler data for the commonly used TR peak velocity method.

Funding Acknowledgement

Type of funding sources: None.

Massive Perivillous Fibrin Deposition and Chronic Histiocytic Intervillositis a Complication of SARS-CoV-2 Infection

An emerging complication of COVID-19 (SARS-CoV-2) infection is reported. A 23-year-old patient presented with high temperature and reduced fetal movements at 25 + 5/40 weeks of gestation. RT-PCR proved maternal COVID-19 infection. Ultrasound examination confirmed intrauterine death. Placenta histology showed necrosis of the villous trophoblast, associated with Chronic Histiocytic Intervillositis (CHI) and Massive Perivillous Fibrin Deposition (MPFD) with up to 90% - of the intervillous spaces being involved. Immunohistochemistry showed CD68 positive histiocytes in the intervillous spaces and the villous trophoblast was positive for the COVID-19 spike protein. RNA scope signal was indicative of the presence of the viral genome and active viral replication in the villous trophoblastic cells, respectively. MPFD is a gradually developing end-stage disease with various etiology, including autoimmune and alloimmune maternal response to antigens expressed at the feto-maternal interface and frequently accompanies chronic alloimmune villitis or histiocytic intervillositis. Covid-19 infection is associated with similar pattern of histological changes of the placenta leading to placental insufficiency and fetal death. This case report supports maternal- fetal vertical transmission of SARS-CoV-2 virus leading to placental insufficiency and fetal demise. MPFD and CHI appear to be the typical placental histology for SARS-CoV-2 virus infection associated fetal demise.

Increased right ventricular uptake on (99m Tc)-sestamibi SPECT myocardial perfusion imaging as a marker of elevated pulmonary artery systolic pressure measured by Doppler echocardiography

Funding Acknowledgements

Type of funding sources: None.

Background

Though prior work has been done, the significance of the not uncommon finding of increased right ventricular (RV) tracer uptake in patients undergoing (99m Tc)-sestamibi SPECT myocardial perfusion imaging remains poorly defined and this finding not been systemically integrated into the interpretation of the study, despite likely carrying both diagnostic and prognostic relevance for the patient.

Purpose

To examine if the presence of increased RV tracer uptake in patients undergoing myocardial perfusion imaging with same-day protocol (99m Tc)-sestamibi SPECT is associated with a higher pulmonary artery systolic pressure (PASP) measured non-invasively with transthoracic Doppler echocardiography 

Methods

Patients who underwent myocardial perfusion imaging with same-day protocol (99m Tc)-sestamibi SPECT at a single academic health system between 2017-2020 were retrospectively enrolled. Those patients who had a transthoracic echocardiogram performed within 60 days of the nuclear study with sufficient Doppler data to estimate pulmonary artery systolic pressure(PASP) using the tricuspid regurgitation peak velocity method were included. A right atrial pressure of either 3 mmHg, 8 mmHg, or 15 mmHg was used in the calculation of PASP in keeping with the 2015 American Society of Echocardiography guidelines. The rest images for each nuclear study were reviewed and analyzed for the presence of RV tracer uptake. RV uptake was graded as either 0 or "no RV uptake", 1+ or "partial RV uptake", or  2+ or "complete RV uptake".  The nuclear studies were grouped accordingly and the mean PASP for each group was computed.  The mean PASP was also computed for a combined group of patients who demonstrated either 1+ or 2+ RV uptake. Statistical analysis using a t-test was performed to compare the mean PASP of each patient group. 

Results

193 patients were included in the analysis. Of those, 123(63%) demonstrated "no RV uptake",  58(31%) demonstrated 1+ or "partial RV uptake", and 12(6%) demonstrated 2+ or "complete RV uptake". 70 patients(36%) had either 1+ or 2 + RV uptake. The mean PASP was 27.2 ± 7 mmHg for the "no RV uptake" group, 28.3 ± 9 mmHg for the 1+ RV uptake group and 41. 6 ± 14 mmHg for the 2+ RV uptake group. When combined, patients demonstrating 1+ or 2+ RV uptake had a mean PASP of 30.6 ± 11 mmHg. There was no statistical difference in the mean PASP of the "no RV uptake" group and the 1+ or "partial RV uptake group" (p = 0.434). The difference in mean PASP between the "no RV uptake" group and the combined 1+ or 2+ RV uptake group was statistically significant(p = 0.028). 

Conclusion

In a small single health system sample, patients undergoing (99m Tc)-sestamibi SPECT myocardial perfusion imaging who have either partial or complete RV uptake on rest images have an increased pulmonary artery systolic pressure compared to patients who do not exhibit this finding.

Abstract 2849: Shc1 as a potential metastasis driver gene of breast cancer

In the US, women diagnosed with non-metastatic breast cancer have a 5-year survival rate of approximately 98.8%. However, if women develop metastases the survival rate drops to 27.4%, highlighting the need for a better understanding of the mechanisms that regulate and drive metastasis. Somatically acquired mutations that drive metastasis were originally hypothesized by Nowell in the 1970s; however, to date few candidate metastasis driver mutations have been identified and the role of these mutations in metastasis are not well-understood. Using the PyMT genetically engineered mouse model of luminal metastatic breast cancer, previous work by our group performed whole exome sequencing on pairs of matched primary tumor and metastatic tissues from 65 mice. Analysis of this sequencing data identified recurrent metastasis-specific mutations in members of the Ras signaling pathway. One of the members was the SHC Adaptor Protein 1 (Shc1). Five PyMT animals carried different nucleotide substitutions within the same proline 561 codon that falls within the SH2 domain, suggesting an activating role in metastasis. Furthermore, changing this proline mutation to another amino acid could induce a critical change to the Shc1 protein structure and its function. To investigate the role of Shc1 in breast cancer metastasis, CRISPR was performed engineer Shc1 P561 mutations for in vitro and in vivo assays using a series of mouse mammary cancer cell lines and allograft mouse models. Preliminary evidence suggests the P561 mutations have a role in metastasis. Future experiments will address the consequences of the P561 mutation on Shc1 binding partner interactions and downstream signaling and its effects on breast cancer metastasis.

Citation Format: Megan Majocha, Kent Hunter, Christina Ross. Shc1 as a potential metastasis driver gene of breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2849.

Radiologists are increasingly recommending follow-up of chest radiographs: a 10-year review

PURPOSE

To assess for changes in trends of GP chest radiograph reporting over a 10-year period and to assess if there has been a change in recommendations for follow-up.

METHODS

Retrospective study of an Irish tertiary referral center. The total number of GP-referred chest x-rays performed per year from 2007 to 2017 are recorded. One-hundred male/100 female GP-referred chest x-rays are chosen at random from NIMIS data for each of 2007, 2010, 2013, and 2017. Reports are analyzed with regard to abnormal findings, recommendation for follow-up, and yield of follow-up imaging.

RESULTS

There were 4917 GP CXRs performed in 2007, 4856 in 2010, 5561 in 2013, and 6492 in 2017. Follow-up was recommended in 17 studies(8.5%) in 2007, 19 studies(9.5%) in 2010, 22 studies(11%) in 2013, and 27 studies(13.5%) in 2017. Indications for follow-up recommendation were largely to ensure resolution of infection (52%) or for nodule surveillance (43%). There has been a notable increase in lung nodule follow-up, with suggested follow-ups increasing from 6 in 2007, to 7 in 2010, 9 in 2013, and 14 in 2017, an increase of 58%.

CONCLUSION

Along with the increase in the quantity of GP-referred chest radiographs over the past 10 years, suggestions for follow-up have increased, particularly for nodule surveillance. Reasons for this increase may include lack of availability of CT to GPs for lung cancer screening, insensitivity of plain radiographs to early cancer detection, and possible fear of litigation for missing lesions, making radiologists more cautious.

The genomic landscape of metastasis in treatment-naïve breast cancer models

Metastasis remains the principle cause of mortality for breast cancer and presents a critical challenge because secondary lesions are often refractory to conventional treatments. While specific genetic alterations are tightly linked to primary tumor development and progression, the role of genetic alteration in the metastatic process is not well-understood. The theory of tumor evolution postulated by Peter Nowell in 1976 has yet to be proven in the context of metastasis. Therefore, in order to investigate how somatic evolution contributes to breast cancer metastasis, we performed exome, whole genome, and RNA sequencing of matched metastatic and primary tumors from pre-clinical mouse models of breast cancer. Here we show that in a treatment-naïve setting, recurrent single nucleotide variants and copy number variation, but not gene fusion events, play key metastasis-driving roles in breast cancer. For instance, we identified recurrent mutations in Kras, a known driver of colorectal and lung tumorigenesis that has not been previously implicated in breast cancer metastasis. However, in a set of in vivo proof-of-concept experiments we show that the Kras G12D mutation is sufficient to significantly promote metastasis using three syngeneic allograft models. The work herein confirms the existence of metastasis-driving mutations and presents a novel framework to identify actionable metastasis-targeted therapies.

The majority of breast cancer-associated deaths are due to metastatic disease, the process where cancerous cells leave the primary tumor and spread to a new location in the body, because metastatic tumors often become insensitive to the same therapies that were successful in treating the primary tumor. To date, this complex process has been attributed to dynamic changes in tumor cell gene expression regulated by epigenetic factors. Interestingly, while genomic alterations are accepted drivers of neoplastic transformation, it is unknown if such events contribute to metastatic spread. One reason for this is the limited availability of matched and treatment-naïve primary tumor and metastatic tumor samples from patients for comparative genomic testing. Here we use two pre-clinical mouse models of metastatic breast cancer to test if genomic alterations can drive metastatic capacity. We identified metastasis-specific events of single nucleotide variation and gene amplification in well-known oncogenic genes, as well as lesser known factors. We also show that expression of these mutant factors can drive metastasis of weakly and non-metastatic mouse mammary cancer cell lines when implanted in mice. Crucially, by observing and reporting this untested etiology of metastatic disease, specific genomic events can now be included in efforts to develop targets for metastasis-specific therapies.

Beyond HOSPEX: what is the additional training value of military hospital exercises (HOSPEX)?

BACKGROUND

The use of simulation in clinical environments is a frequently used adjunct to training individuals and teams. The military uses clinical simulation to train large numbers of personnel, standardise patient pathways and sustain specific skills to ensure medical personnel are prepared to deploy in their clinical roles.

METHODS

As part of a North Atlantic Treaty Organization (NATO) exercise, 256 Field Hospital (Reserves) deployed a team of clinicians to simulate a role 2 basic field hospital. This hospital exercise (HOSPEX) involved training, and a 4-day real-time exercise with casualty simulation. A retrospective survey of all clinical personnel was conducted to analyse the utility of the exercise on their understanding of their job role, the workings of the field hospital and their confidence in deploying on operations.

RESULTS

39 personnel were surveyed, with questions graded on a modified Likert scale. 41% had previous operational experience in their current job role. A significantly higher proportion of respondents graded their understanding of their job role, and the field hospital overall, as good or excellent having completed the exercise (p<0.01), and 90% felt more confident in fulfilling their operational role postexercise. 90% of respondents had previous experience of simulation, and 94% of these rated the military simulation as being more beneficial than civilian equivalents.

DISCUSSION

With a shift towards simulation in medical training, opportunities have arisen within HOSPEX to develop additional skills for teams and individuals. Simulation is especially important in personnel who have not had previous operational experience, who may deploy on first time operations in senior clinical and leadership roles.

CONCLUSION

HOSPEXs are perceived as being extremely useful by clinical personnel preparing for future operational deployment. HOSPEX simulation has prepared the military for varied operations since its inception, and the paradigm has potential for extension into civilian training for high intensity medical responses.

Efficacy and cultural appropriateness of psychosocial interventions for paediatric burn patients and caregivers: a systematic review

Background

Paediatric burns are highly painful and traumatising injuries that are overrepresented among Aboriginal and Torres Strait Islander people. Paediatric burn patients’ pain remains poorly managed by pharmacological interventions, leading to increased anxiety, distress, and trauma in patients and their caregivers. Non-pharmacological psychosocial interventions have been suggested as effective in reducing pain and psychological morbidities among paediatric burn patients and their caregivers; however, their degree of effectiveness and appropriateness for Aboriginal and Torres Strait Islander people is unclear.

Methods

A non-date restricted systematic review was conducted through four databases. Studies published in English assessing psychosocial interventions on paediatric burn patients’ physical pain along with theirs and/or their caregiver’s anxiety, distress, or trauma symptoms were identified and included in this review. Included studies were assessed for their ability to reduce one of the outcomes of interests and for their reflection of Aboriginal and Torres Strait Islander peoples’ perspectives of health.

Results

Of the 3178 identified references, 17 were eligible. These include distraction based techniques (n = 8), hypnosis/familiar imagery (n = 2), therapeutic approaches (n = 4), and patient preparation/procedural control (n = 3). Distraction techniques incorporating procedural preparation reduced pain, while discharge preparation and increased ‘patient control’ reduced patient and caregiver anxiety; and internet based Cognitive Behaviour Therapy reduced short-term but not long-term post-traumatic stress symptoms. No interventions reflected Aboriginal and Torres Strait Islander peoples’ perspectives of health; and few targeted caregivers or focused on reducing their symptoms.

Conclusions

The development and assessment of psychosocial interventions to appropriately meet the needs of Aboriginal and Torres Strait Islander paediatric burn patients is required.

Platelets Promote Metastasis via Binding Tumor CD97 Leading to Bidirectional Signaling that Coordinates Transendothelial Migration

Tumor cells initiate platelet activation leading to the secretion of bioactive molecules, which promote metastasis. Platelet receptors on tumors have not been well-characterized, resulting in a critical gap in knowledge concerning platelet-promoted metastasis. We identify a direct interaction between platelets and tumor CD97 that stimulates rapid bidirectional signaling. CD97, an adhesion G protein-coupled receptor (GPCR), is an overexpressed tumor antigen in several cancer types. Purified CD97 extracellular domain or tumor cell-associated CD97 stimulated platelet activation. CD97-initiated platelet activation led to granule secretion, including the release of ATP, a mediator of endothelial junction disruption. Lysophosphatidic acid (LPA) derived from platelets induced tumor invasiveness via proximal CD97-LPAR heterodimer signaling, coupling coincident tumor cell migration and vascular permeability to promote transendothelial migration. Consistent with this, CD97 was necessary for tumor cell-induced vascular permeability in vivo and metastasis formation in preclinical models. These findings support targeted blockade of tumor CD97 as an approach to ameliorate metastatic spread.

Are we Over-Imaging the Obese Patient with Suspected Pulmonary Embolus in Ireland

Aims To assess if there was a significant difference in the number of positive studies for pulmonary embolism between obese and non obese patients. Methods A retrospective analysis of all CTPAs performed in our institution over one year in patients aged 18-50 was performed. Data regarding the diagnosis of pulmonary embolism, the presence of airways disease, other significant chest findings, D dimer values and demographic data including a BMI surrogate was obtained. Results Two hundred and thirty CTPAs were performed in our institution over 12 months. Two hundred and twenty-one were included for analysis, of which 129 were male and 92 were female. Sixty-nine (31%) patients were classified as obese. Eleven (16%) of these had positive studies. One hundred and fifty-two patients were in the non obese category, of which 24 (15%) had positive studies. Conclusions We are not over imaging the obese patient, but are over imaging patients in general with suspected PE, but are exposing a significant number overall, to unnecessary radiation.

The role of microbiota and inflammation in self-judgement and empathy: implications for understanding the brain-gut-microbiome axis in depression

RATIONALE

The gut-brain axis includes bidirectional communication between intestinal microbiota and the central nervous system. Bifidobacterium and Lactobacillus spp. have been implicated in psychological health, such as depression, through various pathways (e.g. inflammation). Research needs a better understanding of direct and indirect effects through examination of psychological factors that make people susceptible to, or offer protection against, depression.

OBJECTIVE

This study investigated the relationships between gut microbiota, inflammation and psychological risk and resilience factors for depression.

METHODS

Forty participants (13 m/27 f) recruited from the general population completed self-report questionnaires for depression, self-judgement, over-identification and affective and cognitive empathy. Faecal and blood samples were taken to assay microbiota (Bifidobacterium; Lactobacillus spp.) and pro-inflammatory molecules (C-reactive protein, CRP and interleukin-6, IL-6), respectively.

RESULTS

Hierarchical regression analyses (controlling for sex, age and the shared variance of risk and resilience factors) showed that (i) cognitive depression was significantly predicted by negative self-judgement and reduced cognitive empathy; (ii) abundance of Lactobacillus spp. was directly related to positive self-judgement but only indirectly to cognitive depression and lower affective empathy (both through self-judgement); and (iii) CRP was the strongest predictor of reduced cognitive empathy, with suppression effects seen for age (negative) and IL-6 (positive) after controlling for CRP.

CONCLUSIONS

Findings suggest that lactobacilli and inflammation may be differentially associated with mood disorder via brain mechanisms underpinning self-judgement and cognitive empathy, respectively. Further trials investigating interventions to increase Lactobacillus spp. in depression would benefit from direct measures of self-judgement and affective empathic distress, whilst those that aim to reduce inflammation should investigate cognitive empathy.

Human papillomavirus and oral and oropharyngeal carcinoma: the essentials

There is a global increase in the prevalence of human papillomavirus (HPV)-driven oropharyngeal squamous cell carcinoma (OPSCC) in Australia and New Zealand. Risk factors for HPV-positive OPSCC are male gender, white race, age older than 40 but younger than 59 years old, having multiple lifetime sex partners, having oro-genital and oro-anal sex. High-risk HPV subtypes play a major role in the pathogenesis of OPSCC, however, they play a much lesser role in oral squamous cell carcinoma (OSCC). Among the laboratory tests used to detect oncogenic HPV infection, polymerase chain reaction is a sensitive method but does not reflect the role of HPV in oncogenesis. While widely used, p16 immunohistochemistry is both a sensitive and a specific surrogate marker for oncogenic HPV infection in OPSCC, but not in OSCC. However, it is a useful prognostic marker in OPSCC. The current gold standard to accurately detect oncogenic HPV infection is E6/E7 mRNAin situ hybridization. Because both HPV-positive and p16-positive OPSCC have better short-term prognoses there is current debate and trials on treatment de-escalation in HPV-positive OPSCC. Dental practitioners can play an important role in early diagnosis of HPV-positive OPSCC.

Abstract 3050: Polymorphisms in the arntl2 promoter affect breast cancer metastasis susceptibility

Breast cancer mortality is primarily due to metastatic lesions rather than primary tumors, yet relatively little is known regarding the mechanisms of metastatic breast cancer, making it difficult to identify patients who are at risk for metastatic disease. Our hypothesis suggests that inherited germline mutations contribute to metastatic disease and that these single nucleotide polymorphisms (SNPs) could be used to predict outcome in breast cancer patients. To investigate the effect of inherited SNPs on metastasis, we used a mouse genetics approach comparing strains with high (FVB) and low (MOLF) metastatic phenotypes and identified Arntl2, a circadian rhythm transcription factor, as a gene whose differential expression predicted outcome in breast cancer patients. To identify SNP differences in Arntl2 between MOLF and FVB, we performed whole genome sequencing of MOLF and compared it to the FVB genome. Overlapping the data with DNase hypersensitivity sites revealed 10 SNPs in the predicted promoter of Arntl2. To test the causative role of the SNPs on Arntl2 expression in vivo, metastatic cell lines were engineered using the CRISPR-Cas9 approach to specifically replace the FVB Arntl2 promoter with that of MOLF. In agreement with our hypothesis, substitution of the MOLF promoter reduced Arntl2 transcript levels and subsequently decreased lung metastases in orthotopic implantation assays. In vitro pulldown experiments with strain-specific promoter probes revealed potential differential binding of chromatin modifier proteins, demonstrating the significance of the SNPs in regulating Arntl2 transcription. Finally, analysis of SNPs associated with Arntl2 expression in a cohort of Chinese breast cancer patients revealed significant correlation of Arntl2 expression with overall survival, validating this gene as a marker in humans. Since Arntl2 is a transcription factor, current studies are focused on identifying Arntl2-regulated genes to investigate downstream pathways involved in metastasis. This study has important implications regarding the role of circadian rhythm in cancer progression and provides a potential mechanism to explain the increased risk of breast cancers in nightshift workers. Furthermore, this provides the first evidence that transcriptional control elements can be engineered using CRISPR-Cas9 to establish the causative role of SNPs in inherited susceptibility to cancer metastasis.

Citation Format: Ngoc-Han Ha, Kent Hunter. Polymorphisms in the arntl2 promoter affect breast cancer metastasis susceptibility [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3050. doi:10.1158/1538-7445.AM2017-3050

Abstract 2850: A systems genetics approach reveals Rnaseh2c-immune response axis that affects metastasis severity in breast cancer

Metastatic breast cancer is a devastating disease with a 5-year survival rate of only 26%. This is due to a lack of effective therapies against established metastases and an inability to identify high risk patients who would benefit from specific adjuvant therapies to prevent metastatic progression. We have shown in mouse models that spontaneously arising tumors metastasize with different severity based on the mouse genetic background. Using systems genetics approaches we have identified genes correlated with metastasis and survival in both mice and humans. Rnaseh2c was identified as a novel candidate metastasis susceptibility gene. This gene encodes a scaffolding subunit of the Ribonuclease H2 enzyme which removes ribonucleotides misincorporated into the DNA. Experimentally modulating Rnaseh2c expression in a murine mammary cancer cell line resulted in significant changes in pulmonary metastasis, confirming this gene as a metastasis modifier. Mutations in Rnaseh2c are known to cause Aicardi-Goutieres Syndrome, a neurological autoinflammatory disorder that overlaps clinically with congenital viral infections and the autoimmune disease Systemic Lupus Erythematosus. Given this, we hypothesized that altered expression of Rnaseh2c in breast cancer cells affects metastasis by engaging the immune system. To investigate immune system involvement, we analyzed metastasis in immunocompromised mice. T cell deficiency ablated the effect of reduced Rnaseh2c expression on metastasis, revealing for the first time an Rnaseh2c-immune response axis in metastasis. Gene ontology pathway analysis following mRNA-sequencing of Rnaseh2c knockdown and overexpression tumors revealed that 20% of the genes with altered expression are involved in immune system-related pathways, including T cell signaling and antigen presentation. Furthermore, genes with significant changes included Type I interferons, T cell markers, and immune regulators. These results confirm that Rnaseh2c is a novel metastasis modifier gene and validate our hypothesis that the immune system is mediating the effect of Rnaseh2c on metastasis. This mechanism highlights a potential new target for combination with immune modulatory therapies to combat this devastating disease and adds to a panel of genes we identified that together could determine patients with high risk for metastasis.

Citation Format: Sarah Deasy, Kent Hunter. A systems genetics approach reveals Rnaseh2c-immune response axis that affects metastasis severity in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2850. doi:10.1158/1538-7445.AM2017-2850

Errors in interpretation of neck levels in postoperative pathological specimens

Accurate orientation of pathological specimens is of fundamental importance, and specimens that are divided postoperatively may be misinterpreted. We asked surgeons and pathologists to identify boundaries between nodal levels on a clinical photograph of a neck dissection specimen. Few participants were able to identify the boundaries between levels accurately, with several important errors where a marked level contained none of the relevant anatomical tissue. Most errors were in level I, and the number decreased towards level IV. Errors were made by both pathologists and surgeons. The boundaries of level IIA were consistently overestimated, which may have implications for previous studies that evaluated patterns of nodal spread.

Abstract B28: Identification of breast cancer metastasis promoting genes by next generation sequencing

Breast cancer is a leading cause of cancer-related mortality of women in the United States. The majority of cancer deaths are due to metastases rather than the primary tumor, therefore a better understanding of the mechanisms that lead to metastatic disease is critical to reducing breast cancer-related mortality. A majority of cancer cells that leave the primary tumor are either removed by the immune system or fail to survive in distant organs. However, some cancer cells acquire molecular features that allow them to survive and proliferate in secondary sites, such as lung, liver, brain, and bone. In order to design highly efficient anti-metastatic therapies, it is crucial to address metastasis-specific mechanisms of growth and survival. One of the major hurdles to developing these therapies is the genotypic and phenotypic heterogeneity between primary tumors and metastases, as well as between individual metastases. The goal of this project is to characterize the transcriptomic landscape of breast cancer metastases using Next Generation Sequencing (NGS) tools in order to identify potential genes that drive (metastasis promoters) or inhibit (metastasis suppressors) the metastatic outgrowth in distant organs. Therefore, RNA sequencing was performed on breast cancer primary tumors and matching lung metastases from two different mouse models: Polyomavirus Middle-T antigen (PyMT) transgenic mice, a model of spontaneous and highly aggressive breast cancer, as well as from mouse mammary cancer cells orthotopically injected into FVB mice. RNA sequencing using the NGS platform revealed genes that were highly expressed in metastases compared to primary tumors. Interestingly, overlapping the RNA-seq datasets from these two distinct models revealed a shared subset of upregulated genes, strongly suggesting that these genes are likely to be common metastatic outgrowth promoters. To validate these candidate genes, we are currently developing a CRISPR sgRNA library for orthotopic transplant experiments. The genes displaying in vivo effects on metastatic outgrowth in the lungs will be further explored for the development of targeted anti-metastatic therapies.

Citation Format: Karol Szczepanek, Kent Hunter. Identification of breast cancer metastasis promoting genes by next generation sequencing. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Metastasis; 2015 Nov 30-Dec 3; Austin, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(7 Suppl):Abstract nr B28.

Abstract B30: Rnaseh2c is a candidate metastasis susceptibility gene in breast cancer

Breast cancer is a leading cause of cancer-related female deaths in the United States, the majority of which are due to distant metastases. Elucidating novel genes that drive metastasis is critical to improving patient outcome. Our laboratory has extensively shown that germline variants impact an individual's susceptibility for metastasis, and we have used this to identify novel metastasis modifier genes. Here we applied a mouse model of spontaneous metastasis to a mouse breeding scheme to screen for strain-specific haplotypes associated with metastatic phenotype. Additional filtering of the haplotype-containing genes was performed for those that were highly expressed in tumors. This screen identified Rnaseh2c, a scaffolding subunit of the Ribonuclease H2 complex which degrades RNA from DNA:RNA heteroduplexes such as those generated during replication and transcription, thus helping maintain genomic stability. Though mutations in RNASEH2C are known to cause the neurological autoinflammatory disorder Aicardi-Goutières Syndrome (AGS), it has not previously been linked to cancer. Given the known pathology of AGS, we hypothesize that differential expression of Rnaseh2c in tumor cells alters tumor progression and metastasis potentially via interaction with the immune system. We directly assessed the effect of tumor cell Rnaseh2c expression on metastasis using in vivo metastasis assays. We implanted into the mammary fat pad tumor cells expressing shRNAs that reduced Rnaseh2c expression and observed significantly fewer pulmonary metastases and reduced tumor burden. To complement this approach, we performed the same metastasis assay with cells overexpressing exogenous Rnaseh2c. In agreement with our initial result, overexpression generated significantly more metastases without affecting primary tumor size, confirming Rnaseh2c as a metastasis modifier. The results thus far validate our approach of employing germline variation in mice to identify novel metastasis modifier genes. Current and future work will focus on elucidating the mechanism by which Rnaseh2c expression impacts metastasis. Specifically, we will determine where Rnaseh2c functions in the metastatic cascade, whether modulated expression disrupts Rnase H2 complex formation, and whether the immune system is involved in mediating this gene's effect on metastasis. Elucidating the mechanism by which this gene acts can contribute to both the development of novel metastasis biomarkers as well as potential therapeutic targets.

Citation Format: Sarah Deasy, Kent Hunter. Rnaseh2c is a candidate metastasis susceptibility gene in breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Metastasis; 2015 Nov 30-Dec 3; Austin, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(7 Suppl):Abstract nr B30.

Hearing in school-aged children with trisomy 21 - results of a longitudinal cohort study in children identified at birth

OBJECTIVES

To report the prevalence of hearing problems and the hearing sequelae in school-aged children with trisomy 21 in a longitudinal study.

DESIGN

All children with trisomy 21 were identified via schools, community-based child development centres, general practitioners, or the universal newborn hearing screen. Audiological data and otorhinolaryngological problems were prospectively entered in to the Audiological Surveillance Programme database from each visit.

SETTING

Retrospective review of the Audiological Surveillance Programme database in the Glasgow area (United Kingdom) of all children reviewed between 2004 and 2012.

PARTICIPANTS

All pre-teenaged children with trisomy 21 of school age (aged 5-12 years old).

MAIN OUTCOME MEASURES

Hearing thresholds, aetiology of hearing loss and management of hearing loss was determined for the cohort of children.

RESULTS

A total of 102 children were included. Fifty-four had normal hearing. Twenty-six had fluctuating otitis media with effusion; five had hearing in normal limits, six were managed with hearing aids, fourteen were managed conservatively, and one had ventilation tube insertion. Fifteen had persistent otitis media with effusion; four had ventilation tube insertion; and nine were managed with hearing aids. Seven had mixed hearing loss with four required hearing aids.

CONCLUSIONS

Otitis media with effusion was the commonest cause of hearing impairment; effusions may fluctuate through the pre-teenaged years, and thus, hearing aids are beneficial. Ventilation tube insertion and bone-conducting hearing aids were useful when ear-level hearing aids were not tolerated. Mixed hearing loss occurred in later years as sensorineural hearing loss developed on a background of otitis media with effusion.

CCL9 Induced by TGFβ Signaling in Myeloid Cells Enhances Tumor Cell Survival in the Premetastatic Organ

Tumor cell survival in the hostile distant organ is a rate-limiting step in cancer metastasis. Bone marrow-derived myeloid cells can form a premetastatic niche and provide a tumor-promoting microenvironment. However, it is unclear whether these myeloid cells in the premetastatic site have any direct effect on tumor cell survival. Here, we report that chemokine CCL9 was highly induced in Gr-1(+)CD11b(+) immature myeloid cells and in premetastatic lung in tumor-bearing mice. Knockdown of CCL9 in myeloid cells decreased tumor cell survival and metastasis. Importantly, CCL9 overexpression in myeloid cells lacking TGFβ signaling rescued the tumor metastasis defect observed in mice with myeloid-specific Tgfbr2 deletion. The expression level of CCL23, the human orthologue for CCL9, in peripheral blood mononuclear cells correlated with progression and survival of cancer patients. Our study demonstrates that CCL9 could serve as a good candidate for anti-metastasis treatment by targeting the rate-limiting step of cancer cell survival. In addition, targeting CCL9 may avoid the adverse effects of TGFβ-targeted therapy.

Abstract 3172: CCL9 induction in myeloid cells of the premetastatic niche enhances tumor cell survival and metastatic colonization

Tumor cell survival in the hostile distant organ is a rate-limiting step in cancer metastasis. Bone marrow-derived myeloid cells can form a premetastatic niche and provide a tumor-promoting microenvironment. However, it is unclear whether these myeloid cells in the premetastatic site have any direct effect on tumor cell survival. Here we report that chemokine CCL9 was highly induced in Gr-1+CD11b+ immature myeloid cells and in premetastatic lung of mice bearing 4T1 mammary tumor and B16 melanoma. Knockdown of CCL9 in myeloid cells decreased tumor cell survival and metastasis. The expression level of CCL23, the human orthologue for CCL9, in peripheral blood mononuclear cells correlated with progression and survival of cancer patients. Our studies identify CCL9 as a key pro-survival factor for cancer cells in the premetastatic organ.

Interestingly, the expression of CCL9 in myeloid cells is regulated by TGF-β signaling as overexpression of CCL9 in myeloid cells lacking TGF-β signaling rescued the tumor metastasis defect observed in mice with myeloid-specific deletion of TGF-β signaling. These data together with our previous report of a fundamental role of myeloid TGF-β signaling in host compromised immune surveillance (Cancer Discovery 2013); demonstrate that myeloid-specific TGF-β signaling constitutes an essential component of the metastasis-promoting puzzle of TGF-β. This finding is different from TGF-β signaling in fibroblasts and a variety of epithelial cells, as well as T cells in which the TGF-β signaling functions as a tumor suppressor. This new understanding of TGF-β at the interface of tumor and host may provide insight into how TGF-β switches from a tumor suppressor to a tumor promoter, a long-standing challenge in cancer biology field. Our study demonstrates that CCL9 could serve as a good candidate for anti-metastasis treatment by targeting the rate-limiting step of cancer cell survival. Additionally, targeting CCL9 may avoid the adverse effects of TGF-β-targeted therapy.

Citation Format: Hannah HY Yan, Yanli Pang, Kent Hunter, Chand Khanna, Li Yang. CCL9 induction in myeloid cells of the premetastatic niche enhances tumor cell survival and metastatic colonization. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3172. doi:10.1158/1538-7445.AM2015-3172

The role of individual inheritance in tumor progression and metastasis

Metastasis, the dissemination and growth of tumor cells at secondary sites, is the primary cause of patient mortality from solid tumors. Metastasis is an extremely complex, inefficient process requiring contributions of not only the tumor cell but also local and distant environmental factors, at both the cellular and molecular level. Variation in the function of any of the steps in the metastatic cascade may therefore have profound implications for the ultimate course of the disease. In addition to the somatic and cellular heterogeneity that can affect cancer outcome, an individual's specific ancestry or genetic background can also significantly influence metastatic progression. These inherited variants not only encoded for metastatic susceptibility but also provided a window to study critical factors that are not easily accessible with current technologies. Furthermore, investigations into inherited metastatic susceptibility enable identification of important molecular and cellular processes that are not subject to mutation and are consequently not detectable by standard cancer genome sequencing strategies. Incorporation of inherited variation into metastasis research therefore provides methods to more comprehensively investigate the etiology of the lethal consequences of tumor progression.

Investigating the effects of an oral fructose challenge on hepatic ATP reserves in healthy volunteers: A (31)P MRS study

BACKGROUND

Impaired homeostasis of hepatic ATP has been associated with NAFLD. An intravenous fructose infusion has been shown to be an effective challenge to monitor the depletion and subsequent recovery of hepatic ATP reserves using (31)P MRS.

AIMS

The purpose of this study was to evaluate the effects of an oral rather than intravenous fructose challenge on hepatic ATP reserves in healthy subjects.

METHODS

Self-reported healthy males were recruited. Following an overnight fast, baseline liver glycogen and lipid levels were measured using Magnetic Resonance Spectroscopy (MRS). Immediately after consuming a 500 ml 75 g fructose drink (1275 kJ) subjects were scanned continuously for 90 min to acquire dynamic (31)P MRS measurements of liver ATP reserves.

RESULTS

A significant effect on ATP reserves was observed across the time course (P < 0.05). Mean ATP levels reached a minimum at 50 min which was markedly lower than baseline (80 ± 17% baseline, P < 0.05). Subsequently, mean values tended to rise but did not reach statistical significance above minimum. The time to minimum ATP levels across subjects was negatively correlated with BMI (R(2) = 0.74, P < 0.005). Rates of ATP recovery were not significantly correlated with BMI or liver fat levels, but were negatively correlated with baseline glycogen levels (R(2) = 0.7, P < 0.05).

CONCLUSIONS

Depletion of ATP reserves can be measured non-invasively following an oral fructose challenge using (31)P MRS. BMI is the best predictor of postprandial ATP homeostasis following fructose consumption.

A multi-megabase copy number gain causes maternal transmission ratio distortion on mouse chromosome 2

Significant departures from expected Mendelian inheritance ratios (transmission ratio distortion, TRD) are frequently observed in both experimental crosses and natural populations. TRD on mouse Chromosome (Chr) 2 has been reported in multiple experimental crosses, including the Collaborative Cross (CC). Among the eight CC founder inbred strains, we found that Chr 2 TRD was exclusive to females that were heterozygous for the WSB/EiJ allele within a 9.3 Mb region (Chr 2 76.9 - 86.2 Mb). A copy number gain of a 127 kb-long DNA segment (designated as responder to drive, R2d) emerged as the strongest candidate for the causative allele. We mapped R2d sequences to two loci within the candidate interval. R2d1 is located near the proximal boundary, and contains a single copy of R2d in all strains tested. R2d2 maps to a 900 kb interval, and the number of R2d copies varies from zero in classical strains (including the mouse reference genome) to more than 30 in wild-derived strains. Using real-time PCR assays for the copy number, we identified a mutation (R2d2WSBdel1) that eliminates the majority of the R2d2WSB copies without apparent alterations of the surrounding WSB/EiJ haplotype. In a three-generation pedigree segregating for R2d2WSBdel1, the mutation is transmitted to the progeny and Mendelian segregation is restored in females heterozygous for R2d2WSBdel1, thus providing direct evidence that the copy number gain is causal for maternal TRD. We found that transmission ratios in R2d2WSB heterozygous females vary between Mendelian segregation and complete distortion depending on the genetic background, and that TRD is under genetic control of unlinked distorter loci. Although the R2d2WSB transmission ratio was inversely correlated with average litter size, several independent lines of evidence support the contention that female meiotic drive is the cause of the distortion. We discuss the implications and potential applications of this novel meiotic drive system.

Serum levels of the progesterone induced blocking factor do not precipitously rise in women with gynecologic cancer in contrast to women exposed to progesterone

PURPOSE

To determine if an immunomodulatory protein (progesterone induced blocking factor [PIBF]) that is progesterone induced and found in higher concentration during pregnancy is similarly found with increased levels in women with gynecologic cancers.

MATERIALS AND METHODS

A newly developed enzyme linked immunoabsorbent assay (ELISA) assay was used to measure PIBF in the sera of six women with various gynecologic cancers and compare them to five controls (three with benign tumors and two having gynecologic procedures for non-tumors.

RESULTS

The PIBF levels in women with gynecologic cancer did not rise precipitously as historical controls of women or men exposed to progesterone. The two highest PIBF levels of the 11 subjects were in women with gynecologic cancer.

CONCLUSIONS

The data suggest that if PIBF helps cancer cells to evade immune surveillance, it probably operates through an intracytoplasmic presence. If an increase in sera PIBF could have been detected in women with gynecologic cancer, then this ELISA test could have been used to detect tumor recurrence. Future studies may concentrate on evaluating intracytoplasmic PIBF to possibly help determine which tumors may respond to progesterone antagonist receptors.

Understanding susceptibility to breast cancer metastasis: the genetic approach

Metastasis is a complex phenotype that is not discrete, is polygenic, varies in range over the entire population and follows non-Mendelian inheritance. Recent evidence indicates that inherited susceptibility affects not only the development of the primary tumor, but is also an important factor in progression and metastasis. Since metastasis accounts for the majority of breast cancer deaths, identification and understanding of the genetic modifiers of metastasis underlies success of personalized therapy. Studies from our laboratory and others have now characterized several metastasis susceptibility factors. While an important step forward, these certainly do not describe the entire metastatic phenomenon and efforts continue to expand this knowledge. Here we review the complex metastatic process and current knowledge on the genetics of breast cancer metastasis, including germline polymorphisms that have been associated with the disease.

A low calorie morning meal prevents the decline of hepatic glycogen stores: a pilot in vivo13C magnetic resonance study

A low dose oral glucose challenge following an overnight fast inhibits further reduction in hepatic glycogen reserves without raising levels above baseline.