Abstract P3-06-06: Novel breast cancer mutational signatures

Background: Our understanding of the biological processes that generate somatic mutations in breast cancer has increased markedly over the past five years. Using the catalog of somatic mutations present in cancer genomes, over 30 “mutational signatures” have been produced. While these provide important insights into the processes responsible for somatic mutation, gaps remain, and the etiology of several signatures remains unknown.

Methods: We have developed a new method in which the specific nucleotide change (e.g., C>T), the codon that each mutation falls in (e.g., GCT), the position in the codon (e.g., 2), and the nucleotides immediately 5' and 3' of the mutation (e.g., 5': C; 3': G) are all considered. The summary of these mutation characteristics forms a mutational profile for each tissue sample. Putting multiple samples' profiles together forms a sparse matrix with the number of samples as rows and the mutation characteristics as columns. Nonsmooth nonnegative matrix factorization was then applied to enable the discovery of intrinsic patterns in this sparse matrix.

Results: Using somatic mutations identified in 1017 breast cancer tissues from The Cancer Genome Atlas (TCGA), we have identified four mutational signatures. Signature A correlates with the well-defined APOBEC signatures and signature B with the “aging” signature, which is the result 5-methylcytosine hydrolysis. Signature C and signature D are potentially new signatures. Signature D is enriched with C:G>A:T mutations; these mostly occur in the middle position of codons, and are enriched with GG(CC) either 5' or 3' of the mutation's sequence context. G>T mutations are known to occur as a consequence of oxidative damage that is not repaired. Guanines are vulnerable as they have the highest vertical oxidation potential of the nucleobases. The 5' guanines in GG sites are especially reactive. We hypothesize that Signature D results from oxidative mutagenesis.

When correlated with clinical phenotypes, the basal subtype is clearly enriched for tumors with the Signature D mutation pattern (exposure level is in 169 basal tumors and in 797 non-basal tumors, p=<0.01), suggesting an etiologic link with basal-like breast cancer. G>T somatic mutations in breast cancer mainly take place during cell replication rather than during transcription. In the normal breast, epithelial cell replication occurs during the luteal phase of the menstrual cycle and during pregnancy, primarily under the direction of progesterone (P). P binds to its receptor (PR) in a subpopulation of PR positive cells where it initiates the transcription of genes including RANKL, with resultant paracrine stimulation (through RANK), of the NF-κB signaling pathway in neighboring cells. The four RANKL genes (TOP2A, MKI67, PBK, CDK1), defined by Nolan et al., are all positively associated with the signature D (P-values < 0.05), suggesting that this type of mutagenesis is associated with RANKL pathway upregulation.

Conclusions: We have identified a potentially new somatic mutational signature, which we have designated as Signature D, which appears to result from exposure of DNA to oxidative stress during replication. It is associated with the basal subtype of breast cancer as well as RANKL- NF-κB pathway upregulation.

Citation Format: Zeng Z, Vo AH, Luo Y, Khan SA, Clare SE. Novel breast cancer mutational signatures [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-06-06.

Cerebral hemodynamic changes after wartime traumatic brain injury

Traumatic brain injury (TBI) is associated with the severest casualties from Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF). From October 1, 2008, the U.S. Army Medical Department initiated a transcranial Doppler (TCD) ultrasound service for TBI; included patients were retrospectively evaluated for TCD-determined incidence of post-traumatic cerebral vasospasm and intracranial hypertension after wartime TBI. Ninety patients were investigated with daily TCD studies and a comprehensive TCD protocol, and published diagnostic criteria for vasospasm and increased intracranial pressure (ICP) were applied. TCD signs of mild, moderate, and severe vasospasms were observed in 37%, 22%, and 12% of patients, respectively. TCD signs of intracranial hypertension were recorded in 62.2%; 5 patients (4.5%) underwent transluminal angioplasty for post-traumatic clinical vasospasm treatment, and 16 (14.4%) had cranioplasty. These findings demonstrate that cerebral arterial spasm and intracranial hypertension are frequent and significant complications of combat TBI; therefore, daily TCD monitoring is recommended for their recognition and subsequent management.

Can a self-expanding aneurysm stent be clipped? Emergency proximal control options for the vascular neurosurgeon

BACKGROUND

If a self-expanding stent has been placed during endovascular treatment of an aneurysm and subsequently an open aneurysm surgery becomes necessary in the same or an adjacent area, is it possible and safe to obtain proximal control by placing a temporary clip on the artery at a point where it contains the stent?

OBJECTIVE

To evaluate the effect of temporary clip application to 3 separate stent systems in an in vitro flow model with the stated hypothesis that clip application to these stents will result in permanent stent deformation.

METHODS

This is an in vitro flow model study using an accepted synthetic blood vessel substitute. The Neuroform(3) (Boston Scientific), Enterprise (Cordis/Codman), and Pipeline (ev3) stents were deployed within the flow model; temporary clips were applied; and angiographic measurements subsequently made.

RESULTS

Two 4 × 30-mm Neuroform(3) stents, two 4.5 × 28-mm Enterprise stents, and two 3.75 × 20-mm Pipeline stents were successfully deployed and clipped repeatedly (4 iterations). Two- and 3-dimensional angiograms were obtained. After repeated clip occlusion, the Neuroform(3) and Enterprise stents returned to their original configuration and diameter. Clip application to both also resulted in immediate flow arrest. In contrast, initial clip application to the Pipeline stents did not result in flow arrest, but the second single clip application did. The Pipeline stents were also irreversibly deformed after the experimental protocol, with an average luminal diameter reduction of 26.85% (P < .05).

CONCLUSION

The Neuroform(3) and Enterprise stents responded favorably to temporary clip application, returning to their original diameter after clip removal and showing no sign of permanent structural modification. The Pipeline flow-diverting stent, however, was irreversibly deformed by clip application. These data indicate that temporary clip application to certain stents is possible. Further in vivo study is required.

Wartime Traumatic Aneurysms

OBJECTIVE

Operation Iraqi Freedom has resulted in a significant number of closed and penetrating head injuries, and a consequence of both has been the accompanying neurovascular injuries. Here we review the largest reported population of patients with traumatic neurovascular disease and offer our experience with both endovascular and surgical management.

METHODS

A retrospective analysis of all military casualties returning to the Walter Reed Army Medical Center and the National Naval Medical Center, Bethesda, Maryland, from April 2003 until April 2008 was performed. All patients undergoing diagnostic cerebral angiography during their inpatient stay were included in the study.

RESULTS

A total of 513 war trauma-related consults were performed from April 2003 to April 2008, resulting in the evaluation of 408 patients with closed and penetrating head injuries. In this population, 279 angiographic studies were performed in 187 patients (25 closed craniocervical injuries, 162 penetrating craniocervical injuries), resulting in the detection of 64 vascular injuries in 48 patients (26.2% of those studied, 34% prevalence). Vascular injuries were characterized by traumatic intracranial aneurysms (TICAs) (n = 31), traumatic extracalvarial aneurysms (TECAs) (n = 19), arterial dissections (n = 11), and arteriovenous fistulae (n = 3). The average TICA size on admission was 4.1 mm, with an observed increase in aneurysm size in 11 cases. In the TICA/TECA group, 24 aneurysms in 23 patients were treated endovascularly with either coiling or stent-assisted coiling, resulting in preservation of the parent artery in 12 of 24 vessels (50%). The injuries in 3 patients in this group progressed despite endovascular treatment and required definitive clip exclusion. Thirteen additional aneurysms in 8 patients were treated surgically, resulting in parent artery preservation in 4 cases (30.8%). Eleven of the 13 remaining TICAs/TECAs resolved spontaneously without treatment. A total of 6 aneurysm ruptures (average size, 8.25 mm) occurred, resulting in 3 deaths. Four of 6 ruptures occurred in TICAs in which the interval size increase was noted angiographically.

CONCLUSION

The management of traumatic vascular injury has evolved with technological advancement and the willingness of the neurosurgeon to intervene. Although open surgical intervention remains a viable solution, endovascular options are available and safe and can effectively temporize a patient while acute sequelae of serious head injury resolve.

Transcranial Doppler ultrasonography identifies symptomatic cavum septum pellucidum cyst: case report

OBJECTIVE

Cavum Septum Pellucidum (CSP) cysts are considered normal anatomic variants, comprising as many as 15% of the adult and 85% of pediatric populations. On rare occasions, the cavum can obstruct CSF outflow from the lateral ventricles causing elevated intracranial pressure (ICP) and headaches. The purpose of this paper is to present a challenging case of new onset symptomatic CSP in a previously healthy adult male without papilledema and elevated ICP detected by transcranial Doppler (TCD) ultrasonography.

CLINICAL PRESENTATION

A previously healthy 44 year-old man presented to the neurology service with debilitating positional headaches that were mitigated solely by recumbent positioning. A magnetic resonance imaging scan (MRI) of the brain revealed a cavum septum pellucidum. A lumbar puncture was performed and revealed normal ICP. No papilledema was evident on fundoscopic examination. A CSF flow study revealed normal dye opacification pattern without evidence of CSF leak.

INTERVENTION

Without other clinical indicators of high ICP, but a history suspicious for symptomatic CSP, TCD study was performed and revealed abnormally low cerebral blood flow velocities (CBFV's) and significantly elevated pulsatility indices (PI's) for patient's age indicative of high ICP. Endoscopic fenestration of the septum pellucidum was performed improving the patient's headaches and normalization of the PI's and CBFV's to normal (p<0.01).

CONCLUSIONS

Symptomatic CSP is a difficult diagnosis to make based on existing diagnostic paradigm. TCD in the absence of other objective confirmatory studies, can aid in the diagnosis and provide information about the success of fenestration of the cavum septum.

Post-combat invincibility: violent combat experiences are associated with increased risk-taking propensity following deployment

Combat exposure is associated with increased rates of mental health problems such as post-traumatic stress disorder, depression, and anxiety when Soldiers return home. Another important health consequence of combat exposure involves the potential for increased risk-taking propensity and unsafe behavior among returning service members. Survey responses regarding 37 different combat experiences were collected from 1252 US Army Soldiers immediately upon return home from combat deployment during Operation Iraqi Freedom. A second survey that included the Evaluation of Risks Scale (EVAR) and questions about recent risky behavior was administered to these same Soldiers 3 months after the initial post-deployment survey. Combat experiences were reduced to seven factors using principal components analysis and used to predict post-deployment risk-propensity scores. Although effect sizes were small, specific combat experiences, including greater exposure to violent combat, killing another person, and contact with high levels of human trauma, were predictive of greater risk-taking propensity after homecoming. Greater exposure to these combat experiences was also predictive of actual risk-related behaviors in the preceding month, including more frequent and greater quantities of alcohol use and increased verbal and physical aggression toward others. Exposure to violent combat, human trauma, and having direct responsibility for taking the life of another person may alter an individual's perceived threshold of invincibility and slightly increase the propensity to engage in risky behavior upon returning home after wartime deployment. Findings highlight the importance of education and counseling for returning service members to mitigate the public health consequences of elevated risk-propensity associated with combat exposure.

Modafinil for treatment of fatigue in post-polio syndrome: a randomized controlled trial

OBJECTIVE

To determine if modafinil can improve fatigue in patients with post-polio syndrome.

METHODS

We used a randomized, placebo-controlled crossover trial. Intervention with modafinil (400 mg/day) and placebo occurred over 6-week periods. Primary endpoint (fatigue) was assessed using the Fatigue Severity Scale as the main outcome measure. Other measures included the Visual Analog Scale for Fatigue and the Fatigue Impact Scale. Secondary endpoint (health-related quality of life) was assessed using the 36-Item Short-Form. Analysis of variance for repeated measures was applied to assess treatment, period, and carryover effects.

RESULTS

Thirty-six patients were randomized, 33 of whom (mean age: 61 years) completed required interventions. Treatment with modafinil was safe and well-tolerated. After adjusting for periods and order effects, no difference was observed between treatments.

CONCLUSION

Based on the utilized measures of outcome modafinil was not superior to placebo in alleviating fatigue or improving quality of life in the studied post-polio syndrome population.

Botulinum toxin type-a in the prevention of migraine: a double-blind controlled trial

INTRODUCTION

Migraine is a frequent medical complaint. In military populations, migraine can be detrimental to productivity and troop readiness, and can be disqualifying for service in some military duty specialties. This study assessed the effectiveness of botulinum neurotoxin type-A (BTX-A) in reducing the frequency of migraines in known migraineurs.

METHODS

There were 32 subjects (control = 17, test n = 15) who completed the assessment battery at baseline and monthly for 3 mo. Adult subjects with migraine headaches occurring more than 5 times/month were recruited and randomized to receive placebo saline injection vs. BTX-A. The primary efficacy parameter was the average frequency of headache days for 3 mo. Secondary outcome measures were severity of attacks and quality of life.

RESULTS

Quadratic trends were noted for headache severity (F (2,29) = 14.1, p = 0.001) and headache indexes (F (2,29) = 4.5, p = 0.042) for both groups, suggesting changes in severity of head pain and overall intensity of headaches experienced over time; however, results were not significant for headache frequency and severity between groups. Paired t-tests of the headache index scores for the control group revealed a significant increase from the first to the third follow-up periods (t = -2.58, p = 0.020). Such a trend was not observed for the BTX-A group. Both groups, however, reported similarly low to moderate quality of life as a result of their migraines.

CONCLUSIONS

This controlled trial failed to demonstrate efficacy of BTX-A in reducing the frequency of migraine headaches. The pattern headache index in the botox group, however, suggested a protective effect for botox against the headache severity.

The endovascular operating room as an extension of the intensive care unit: changing strategies in the management of neurovascular disease

Technological advances within the field of endovascular neurosurgery have influenced the management of the neurovascular patient within the intensive care unit (ICU). The endovascular operating room has, in fact, become an extension of the ICU in certain cases. Given the rapid development of new endovascular technologies, it is more important than ever for neurosurgeons to remain intimately involved with the care of their patients within the ICU. This article offers an overview of the evolution in ICU management of neurovascular disease and provides a framework for the incorporation of the endovascular operating room in the intensive care management of patients with this disease.

Wartime traumatic cerebral vasospasm: recent review of combat casualties

OBJECTIVE

Blast-related neurotrauma is associated with the severest casualties from Operation Iraqi Freedom (OIF). A consequence of this is cerebral vasospasm. This study evaluated all inpatient neurosurgical consults related to battle injury from OIF.

METHODS

Evaluation of all admissions from OIF from April 2003 to October 2005 was performed on patients with neurotrauma and a diagnostic cerebral angiogram. Differences between patients with and without vasospasm and predictors of vasospasm were analyzed.

RESULTS

Fifty-seven out of 119 neurosurgical consults were evaluated. Of these, 47.4% had traumatic vasospasm; 86.7% of patients without vasospasm and 80.8% of patients with vasospasm sustained blast trauma. Average spasm duration was 14.3 days, with a range of up to 30 days. Vasospasm was associated with the presence of pseudoaneurysm (P = 0.05), hemorrhage (P = 0.03), the number of lobes injured (P = 0.012), and mortality (P = 0.029). Those with vasospasm fared worse than those without (P = 0.002). The number of lobes injured and the presence of pseudoaneurysm were significant predictors of vasospasm (P = 0.016 and 0.02, respectively). There was a significant quadratic trend towards neurological improvement for those receiving aggressive open surgical treatment (P = 0.002). In the vasospasm group, angioplasty with microballoon significantly lowered middle cerebral artery and basilar blood-flow velocities(P = 0.046 and 0.026, respectively).

CONCLUSION

Traumatic vasospasm occurred in a substantial number of patients with severe neurotrauma, and clinical outcomes were worse for those with this condition. However, aggressive open surgical and endovascular treatment strategies may have improved outcome. This was the first study to analyze the effects of blast-related injury on the cerebral vasculature.

Anesthesia for Endovascular Neurosurgery

Endovascular neurosurgical procedures are complex, requiring significant planning, foresight, and coordination. The neuroanesthetist is an integral part of these procedures, organizing efforts of the technicians and nurses and responding to the needs of the neurointerventionalist. The purpose of this article is to review, in detail, the role of the neuroanesthetist in the endovascular operating room. An overview of all areas either partially or completely managed by the anesthetist is provided.

Multimodal monitoring during emergency hemicraniectomy for vein of Labbe thrombosis

INTRODUCTION

Cortical venous thrombosis is a rarely encountered mechanism for intracerebral hemorrhage. Multimodal monitoring may guide neurosurgical and critical care treatment in the setting of cerebral venous thrombosis.

METHODS

We report a 37-year-old service member who was admitted to a local field hospital for complaints of severe headache and left ear pain during Operation Iraqi Freedom. CT scan revealed a left temporal intracranial hematoma and subarachnoid hemorrhage. Angiogram revealed thrombosis of the vein of Labbe. Intracranial pressure (ICP), brain tissue oxygenation (PbO2), and cerebral blood flow (CBF) were monitored. There was a progressive increase in ICP despite ventricular drainage, sedation, and intubation. There was an ominous decrease in brain tissue oxygen and CBF became undetectable concomitantly with the increase in ICP. There was a dramatic decrease in ICP and improvement in brain tissue oxygenation and CBF after decompression and evacuation of the hematoma. Six weeks after the hemorrhage, the patient was able to follow simple commands and complete short sentences.

DISCUSSION

To our knowledge, this is the first description of the use of ICP, PbO2, and laser Doppler method for obtaining CBF in the same setting. Information obtained from monitoring may lead to timely decompression and avoidance of poor outcome.

A Comparison of Fatigue Scales in Postpoliomyelitis Syndrome

OBJECTIVE

To examine the applicability and validity of traditional fatigue questionnaires in postpoliomyelitis syndrome (PPS) patients with disabling fatigue.

DESIGN

Cross-sectional study. PPS and disabling fatigue were ascertained according to published criteria. Descriptiveness was determined using the McNemar test, and interscale z-score agreement was estimated with Pearson's coefficients.

SETTING

PPS clinic.

PARTICIPANTS

Fifty-six survivors of poliomyelitis: 39 met criteria for PPS, 25 of whom met criteria for disabling fatigue.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The Fatigue Severity Scale (FSS), visual analog scale (VAS) for fatigue, and Fatigue Impact Scale (FIS).

RESULTS

Twenty-four patients scored 50% or higher on the scale range for FSS, compared with 19 patients for VAS for fatigue (P=.042), and 7 patients for FIS (P<.001). Scores for patients with disabling fatigue averaged 81.5%, 62%, and 40.9% of the scale range for FSS, VAS for fatigue, and FIS, respectively. Agreement was moderate between the FSS and VAS for fatigue (r=.45, P=.02), but low between FSS and FIS (r=.29, P=.15), and FIS and VAS for fatigue (r=.20, P=.33). Two sample t tests showed significant differences between those with disabling fatigue and those without, based on FSS scores (t=3.8, P<.001), but not for VAS for fatigue or FIS scores.

CONCLUSIONS

FSS was the most descriptive of the instruments tested. Scores generated by the scales were not interchangeable. Of the 3 scales, FFS seemed to be the most informative for the clinical assessment of fatigue in patients with PPS.

Assessing risk propensity in American soldiers: preliminary reliability and validity of the Evaluation of Risks (EVAR) scale--English version

Risk-taking propensity is a critical component of judgment and decision-making in military operations. The Evaluation of Risks scale (EVAR) was recently developed to measure state and trait aspects of risk proneness. The scale, however, was psychometrically normed in French and no data are available for the English translation. We administered the English version of the EVAR to 165 U.S. soldiers to obtain reliability, validity, and normative data for English-speaking respondents. Confirmatory factor analysis suggested that the factor structure of the English EVAR differs from that obtained in the French studies. Instead, a three-factor solution, including recklessness/impulsivity, self-confidence, and need for control, emerged. Internal consistency was comparable to the French version. EVAR scores correlated with age, military rank, and years of service, and discriminated soldiers with histories of high-risk behavior. The data support the reliability and validity of the English version of the EVAR for evaluating risk propensity in U.S. soldiers.

Eosinophilic meningitis after implantation of a rifampin and minocycline-impregnated ventriculostomy catheter in a child. Case report

Eosinophilic meningitis has been defined as meningitis in which a total cerebrospinal fluid (CSF) sample is found to have more than 10 eosinophils per millimeter or is composed of greater than 10% eosinophils. The differential diagnosis is broad and the clinical presentation, lacking an internalized CSF diversion system, is often nonspecific. With respect to patients with shunt systems, a positive correlation exists between CSF eosinophilia and eventual shunt failure requiring revision. In this paper the authors present the highest reported level of CSF eosinophilia in conjunction with a rifampin and minocycline-impregnated ventriculostomy catheter recently approved by the Food and Drug Administration.

Effects of Perceived Treatment on Quality of Life and Medical Outcomesin a Double-blind Placebo Surgery Trial

CONTEXT

This study was part of a large double-blind sham surgery-controlled trial designed to determine the effectiveness of transplantation of human embryonic dopamine neurons into the brains of persons with advanced Parkinson's disease. This portion of the study investigated the quality of life (QOL) of participants during the 1 year of double-blind follow-up.

OBJECTIVES

To determine whether QOL improved more in the transplant group than in the sham surgery group and to investigate outcomes at 1 year based on perceived treatment (the type of surgery patients thought they received).

DESIGN

Participants were randomly assigned to receive either the transplant or sham surgery. Reported results are from the 1-year double-blind period.

SETTING

Participants were recruited from across the United States and Canada. Assessment and surgery were conducted at 2 separate university medical centers.

PARTICIPANTS

A volunteer sample of 40 persons with idiopathic Parkinson's disease participated in the transplant ("parent") study, and 30 agreed to participate in the related QOL study: 12 received the transplant and 18 received sham surgery.

INTERVENTIONS

Interventions in the parent study were transplantation and sham brain surgery. Assessments of QOL were made at baseline and 4, 8, and 12 months after surgery.

MAIN OUTCOME MEASURES

Comparison of the actual transplant and sham surgery groups and the perceived treatment groups on QOL and medical outcomes. We also investigated change over time.

RESULTS

There were 2 differences or changes over time in the transplant and sham surgery groups. Based on perceived treatment, or treatment patients thought they received, there were numerous differences and changes over time. In all cases, those who thought they received the transplant reported better scores. Blind ratings by medical staff showed similar results.

CONCLUSIONS

The placebo effect was very strong in this study, demonstrating the value of placebo-controlled surgical trials.

Does personality change as a result of fetal tissue transplantation in the brain?

This study examined the effects on personality of transplantation of fetal tissue into the brains of participants in a double-blind placebo control trial for the treatment of Parkinson's disease (PD). Thirty persons with PD (equal numbers of males and females) participated in a larger study investigating the efficacy of transplantation of fetal neural tissue versus placebo surgery. Participants were randomly assigned to receive either the fetal transplant or placebo surgery. The blind was lifted for all patients approximately 13 months after surgery, at which time individuals who had received the placebo surgery could choose to receive the transplant surgery. In this study 12 persons originally received the transplant and 18 received placebo surgery. The NEO Five-Factor Inventory (NEO-FFI), a commonly used measure of personality characteristics, was administered to participants at baseline, 12, and 24 months after surgery. Scores at baseline for the Openness and Agreeableness scales were significantly higher for this sample of PD patients than scores for the normative group. There were no changes on any of the five scales from baseline to 12 months for the total group. The only significant change in the original transplant group was a decrease in Conscientiousness from baseline to 24 months. There were no changes over time among the group who had placebo surgery first and then the transplant. Results indicate that personality, as measured by the NEO-FFI, basically remained stable during the two-year follow-up period of this study. In this case, no change is regarded as a positive outcome.

The epidemiology of typhoid fever in the Dong Thap Province, Mekong Delta region of Vietnam

A population-based surveillance for typhoid fever was conducted in three rural communes of Dong Thap Province in southern Vietnam (population 28,329) for a 12-month-period starting on December 4, 1995. Cases of typhoid fever were detected by obtaining blood for culture from residents with fever > or = 3 days. Among 658 blood cultures, 56 (8.5%) were positive for Salmonella typhi with an overall incidence of 198 per 10(5) population per year. The peak occurrence was at the end of the dry season in March and April. The attack rate was highest among 5-9 year-olds (531/10(5)/year), and lowest in > 30 year-olds (39/10(5)/year). The attack rate was 358/10(5)/year in 2-4 year-olds. The isolation of S. typhi from blood cultures was highest (17.4%) in patients with 5 to 6 days of fever. Typhoid fever is highly endemic in Vietnam and is a significant disease in both preschool and school-aged children.