Factors associated with discontinuation of treatment for pulmonary arterial hypertension in the United States.

Information on factors leading to pulmonary arterial hypertension (PAH) treatment discontinuation is limited. This study analyzed 12,902 new PAH medication users to identify predictors of treatment discontinuation. Treatment by accredited pulmonary hypertension centers and combination therapy with PAH agents from different classes were less likely to result in discontinuation.

27-gene Immuno-Oncology (IO) Score is Associated With Efficacy of Checkpoint Immunotherapy in Advanced NSCLC: A Retrospective BC Cancer Study.

BACKGROUND: Immune checkpoint inhibitors (ICI) are standard of care in advanced non-small cell lung cancer (NSCLC). However, not all patients benefit, even among PD-L1 tumor proportional score (TPS) ≥50%, indicating an unmet need for additional biomarkers such as those assessing the tumor immune microenvironment (TIME). DetermaIO is a 27-gene assay that classifies TIME and has previously demonstrated association with ICI response. METHODS: FFPE samples were selected from BC Cancer and West Clinic Cancer Center patients with performance status (PS) ≤2 who received at least 2 cycles of ICI monotherapy in the first (1L) or second line (2L). IO scores were generated and analyzed for association with PFS and OS. RESULTS: In the entire cohort (N=147), IO score was significantly associated with OS (HR=0.68, 95%CI 0.47-0.99, P = .042) and PFS (HR=0.62, 95%CI 0.43-0.88, P = .0069). In 1L treated patients (PD-L1≥50%, N=78), IO score was significantly associated with PFS (HR=0.55, 95%CI 0.32-0.94, P = .028). In exploratory analyses, IO score was associated with benefit in 1L PS2 patients for OS (HR = 0.26, 95%CI 0.091-0.74, P = .012) and PFS (HR = 0.27, 95%CI 0.098-0.72, P = .0095) which was confirmed in PFS subgroup analysis in the independent West Cancer Center study (N=13 HR=0.14, 95%CI 0.027-0.76, P = .023). CONCLUSION: These data confirm the association of DetermaIO with ICI clinical benefit in NSCLC, and expand on previous studies by demonstrating that first line treated PD-L1≥50% patients can further be stratified by IO score to identify efficacy. Exploratory analysis suggested that the IO score identifies benefit in patients with poor PS.

Immune related adverse events and treatment discontinuation in patients older and younger than 75 years with advanced melanoma receiving nivolumab or pembrolizumab.

BACKGROUND: Programmed cell-death 1 antibodies (PD-1 Ab) improve overall survival (OS) for patients with advanced melanoma in trials; however, safety data in patients ≥75 years are lacking. The prognostic significance of and risk factors for PD-1 Ab discontinuation due immune related adverse events (irAE) are also uncertain. METHODS: Patients with advanced melanoma receiving frontline PD-1 Ab at British Columbia Cancer outside of clinical trials between 10/2015-10/2019 were retrospectively analyzed. The incidence and subtypes of irAE were compared between age subgroups <75 and ≥ 75 years. Univariable logistic regression identified variables associated with treatment discontinuation within four months of PD-1 Ab initiation. Cox proportional hazard regression models were used to determine factors significantly associated with OS. RESULTS: 302 patients were identified, of whom 126 (41.7%) were ≥ 75 years. During all follow-up, 15.9% of patients experienced irAE grade 3/4 and 27.2% of the cohort stopped PD-1 Ab due to immune toxicity. irAE incidence, hospitalization, and need for steroids by the four-month landmark were similar amongst age groups. Advanced age was not associated with risk of PD-1 Ab discontinuation from irAE on logistic regression. For the entire cohort, pre-treatment factors associated with shorter OS on multivariable analysis were ECOG performance status ≥1, M1d stage, lactate dehydrogenase >224, and neutrophil/ lymphocyte ratio ≥ 5. On four-month landmark multivariable analysis, treatment discontinuation due to irAE was significantly associated with worse OS. CONCLUSION: Patients aged ≥75 years experienced similar irAE rates and treatment discontinuation for immune toxicity compared to younger patients. As PD-1 Ab discontinuation due to irAE was associated with shorter OS, efforts to treat irAE early are warranted to potentially avoid therapy cessation.

Time to Treatment With Nivolumab or Pembrolizumab for Patients With Advanced Melanoma in Everyday Practice.

Background The anti-programmed cell death one antibodies (Anti-PD-1 Ab) pembrolizumab or nivolumab are commonly prescribed to patients with advanced melanoma. The purpose of the current study is to identify baseline clinical characteristics associated with time to treatment initiation (TTI) of pembrolizumab or nivolumab for advanced melanoma and whether treatment delays are associated with differences in survival outcomes. Methods All patients receiving Anti-PD-1 Ab as a first-line treatment for advanced melanoma outside of clinical trials at British Columbia Cancer Agency between 10/2015 and 10/2019 were identified retrospectively. TTI was defined as the interval from pathologic diagnosis of advanced melanoma to first Anti-PD-1 Ab treatment. To determine the association between TTI and baseline characteristics, multivariable Cox proportional hazard regression analyses provided an estimate of the instantaneous relative risk of starting treatment at any time point (hazard ratio [HR] >1 indicates shorter TTI). To describe changes in overall survival (OS) observed for each four-week delay in treatment initiation, multivariable cox proportional hazard regression modelling was also performed. Results In a cohort of 302 patients, the median TTI was 52 days (interquartile range 30.2-99.0). Pulmonary metastases (M1b)/non-central nervous system visceral metastases (M1c) vs. metastases to skin or non-regional lymph nodes (M1a)(HR=1.50, 95% CI=1.12-2.02; p=0.007) and pre-treatment Eastern Cooperative Oncology Group Performance Status (ECOG PS) >1 (vs 0/1, HR=1.50, 95% CI= 1.11-2.01; p=0.008) were associated with earlier TTI. An association between treatment delay and improved OS was observed. Conclusion Patients having visceral metastases and poor baseline ECOG PS were more likely to initiate Anti-PD-1 Ab sooner. The association of shorter TTI with worse OS likely represents confounding by indication (urgent treatment offered to patients with aggressive disease).

Prognostic significance of the neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio for advanced non-small cell lung cancer patients with high PD-L1 tumor expression receiving pembrolizumab.

BACKGROUND: We investigated the association of peripheral blood inflammatory markers with overall survival (OS) in pembrolizumab treated advanced non-small cell lung cancer (aNSCLC) patients with programmed death ligand 1 (PD-L1) expression ≥50%. Clinical risk factors for development of immune-related adverse events (irAE) were also explored. METHODS: aNSCLC patients with high PD-L1 expression receiving pembrolizumab monotherapy outside of clinical trials were identified retrospectively. All patients were treated at one of six British Columbia Cancer clinics between August 2017 and June 2019. Patients were dichotomized using baseline neutrophil-to-lymphocyte ratio (NLR,

Association of age with differences in immune related adverse events and survival of patients with advanced nonsmall cell lung cancer receiving pembrolizumab or nivolumab.

OBJECTIVES: To explore the association of age with development of immune related adverse events (irAE) and survival in patients with advanced nonsmall cell lung cancer (aNSCLC) receiving programmed cell death 1 antibodies (PD-1 Ab) outside of clinical trials. METHODS: A multicenter retrospective study of PD-1 Ab prescription for patients with aNSCLC between 06/2015-11/2018 at BC Cancer. Multivariable (MVA) logistic regression identified baseline variables associated with irAE manifested within 3 months of PD-1 Ab initiation. Overall survival (OS) analyzed in a propensity-score matched cohort and survival outcomes compared between age groups by stratified log-rank. Six-week landmark analysis was performed and OS compared between patients with interrupted versus continuous treatment by log-rank. RESULTS: Of 527 patients, 40.6% were age ≤ 64 years, 40.6% were 65-74 years, and 18.8% were ≥ 75 years. In MVA, ECOG performance status 2/3 (p = .034), squamous histology (p = .031), and nivolumab therapy (vs. pembrolizumab, p = .012) were associated with increased odds of irAE by 3 months of treatment. Across age groups no difference existed in any grade irAE (p = .98), hospitalization (p = 1.0), or corticosteroids use (p = .51). The propensity score-matched survival analysis comprised 77 patients from each age group; all covariates were balanced. OS did not differ significantly by age in the matched cohort (p = .17). Treatment interruption due to irAE at 6 weeks was more common in patient ≥75 years (vs. <75, p = .055) and correlated with lower OS (p = .002). CONCLUSION: In this cohort of patients with aNSCLC treated in routine clinical practice with PD-1 Ab, immune-toxicity and observed survival were similar amongst age groups.

White Matter Hyperintensity Volume Influences Symptoms in Patients Presenting With Minor Neurological Deficits.

Background and Purpose- Acute minor neurological deficits are a common complaint in the emergency department and differentiation of transient ischemic attack/minor stroke from a stroke mimic is difficult. We sought to assess the ability of white matter hyperintensity (WMH) volume to aid the diagnosis in such patients. Methods- This is a post hoc analysis of the previously published SpecTRA study (Spectrometry in TIA Rapid Assessment) of adult patients that presented to the emergency department with acute minor neurological deficits between December 2013 and March 2017. WMH volumes were measured if fluid-attenuated inversion recovery imaging was available. Outcomes of interest were final diagnosis, symptoms at presentation, and 90-day stroke recurrence. Results- WMH volume was available for 1485 patients. Median age was 70 years (interquartile range, 59-80), and 46.7% were female. Mean WMH volume was higher in transient ischemic attack/minor strokes compared with stroke mimics (1.71 ln mL [95% CI, 1.63-1.79 ln mL] versus 1.15 ln mL [95% CI, 1.02-1.27 ln mL], P<0.001). In multivariable-adjusted logistic regression analysis, WMH volume was not associated with final diagnosis. However, the combination of both diffusion-weighted imaging positivity and high WMH volume led to lower odds of focal symptoms at presentation (P=0.035). Conclusions- The combination of diffusion-weighted imaging positivity and high WMH volume was associated with lower odds of focal symptoms at presentation in patients seen with minor neurological deficits in the emergency department. This suggests that WMH volume might be an important consideration and the absence of focal symptoms at presentation should not discourage clinicians from further investigating patients with suspected cerebral ischemia.

Systolic blood pressure as a predictor of transient ischemic attack/minor stroke in emergency department patients under age 80: a prospective cohort study.

BACKGROUND: Elevated blood pressure (BP) at emergency department (ED) presentation and advancing age have been associated with risk of ischemic stroke; however, the relationship between BP, age, and transient ischemic attack/minor stroke (TIA/MS) is not clear. METHODS: A multi-site, prospective, observational study of 1084 ED patients screened for suspected TIA/MS (symptom onset < 24 h, NIHSS< 4) between December 2013 and April 2016. Systolic and diastolic BP measurements (SBP, DBP) were taken at ED presentation. Final diagnosis was consensus adjudication by stroke neurologists; patients were diagnosed as either TIA/MS or stroke-mimic (non-cerebrovascular conditions). Conditional inference trees were used to define age cut-points for predicting binary diagnosis (TIA/MS or stroke-mimic). Logistic regression models were used to estimate the effect of BP, age, sex, and the age-BP interaction on predicting TIA/MS diagnosis. RESULTS: Over a 28-month period, 768 (71%) patients were diagnosed with TIA/MS: these patients were older (mean 71.6 years) and more likely to be male (58%) than stroke-mimics (61.4 years, 41%; each p < 0.001). TIA/MS patients had higher SBP than stroke-mimics (p < 0.001). DBP did not differ between the two groups (p = 0.191). SBP was predictive of TIA/MS diagnosis in younger patients, after accounting for age and sex; an increase of 10 mmHg systolic increased the odds of TIA/MS 18% (odds ratio [OR] 1.18, 95% CI 1.00-1.39) in patients < 60 years, and 23% (OR 1.23, 95% CI 11.12-1.35) in those 60-79 years, while not affecting the odds of TIA/MS in patients ≥80 years (OR 0.99, 95% CI 0.89-1.07). CONCLUSIONS: Raised SBP in patients younger than 80 with suspected TIA/MS may be a useful clinical indicator upon initial presentation to help increase clinicians' suspicion of TIA/MS. TRIAL REGISTRATION: ClinicalTrials.gov NCT03050099 (10-Feb-2017) and NCT03070067 (3-Mar-2017). Retrospectively registered.

Pembrolizumab for advanced nonsmall cell lung cancer: Efficacy and safety in everyday clinical practice.

OBJECTIVES: While pembrolizumab improves overall survival (OS) in a subset of advanced nonsmall cell lung cancer (aNSCLC) patients (pts) in clinical trials, individuals with poor Eastern Cooperative Oncology Group performance status (ECOG PS) were excluded. Furthermore, some studies have identified a potential link between improved pt outcomes and development of immune related adverse events (irAE.) In a large provincial cohort, we studied the efficacy and safety of pembrolizumab for poor ECOG PS pts and whether irAE correlate with improved OS. MATERIALS AND METHODS: aNSCLC pts treated with pembrolizumab between 06/2015 and 08/2018 at BC Cancer were retrospectively identified. Kaplan-Meier curves of OS from initiation of pembrolizumab were plotted. 3-, 6-, and 9- month landmark Kaplan-Meier analysis was performed and log-rank tests used to determine an association of irAE subtypes with OS. Multivariable logistic regression identified variables associated with grade ≥3 irAE within 3 months of pembrolizumab initiation. RESULTS: Of 190 pts, 74.2% were treatment naïve and 92.6% had PD-L1 expression ≥ 50%. Median OS in the 1st line and ≥2nd line settings were 24.3 months (95% CI, 9.7-not reached, NR) and 13.4 months (95% CI, 8.1-NR), respectively. Pts with ECOG PS 2/3 had lower median OS than if ECOG PS 0/1 (5.8 months vs. 16.7 months, p < 0.0001). In multivariable analysis, the odds of grade ≥ 3 irAE within 3 months was 6.3 fold higher if ECOG PS 2/3 versus 0/1 (p = 0.05). Development of pneumonitis at the 9 month landmark weakly correlated with decreased OS (p = 0.09). CONCLUSION: In the studied cohort, ECOG PS 2/3 pts had a significantly lower OS and greater odds of experiencing high-grade irAE than if ECOG PS 0/1. Development of irAE did not result in improved OS. Randomized trials to determine benefit of pembrolizumab for poor ECOG PS pts are needed.

Sex Differences in Presentation and Outcome After an Acute Transient or Minor Neurologic Event.

IMPORTANCE: Sex differences have been described in the presentation, care, and outcomes among people with acute ischemic strokes, but these differences are less understood for minor ischemic cerebrovascular events. The present study hypothesized that, compared with men, women are more likely to report nonfocal symptoms and to receive a stroke mimic diagnosis. OBJECTIVE: To evaluate sex differences in the symptoms, diagnoses, and outcomes of patients with acute transient or minor neurologic events. DESIGN, SETTING, AND PARTICIPANTS: This prospective cohort study of patients with minor ischemic cerebrovascular events or stroke mimics enrolled at multicenter academic emergency departments in Canada between December 2013 and March 2017 and followed up for 90 days is a substudy of SpecTRA (Spectrometry for Transient Ischemic Attack Rapid Assessment). In total, 1729 consecutive consenting patients with acute transient or minor neurologic symptoms were referred for neurologic evaluation; 66 patients were excluded for protocol violation (n = 46) or diagnosis of transient global amnesia (n = 20). EXPOSURES: The main exposure was female or male sex. MAIN OUTCOMES AND MEASURES: The main outcome was the clinical diagnosis (cerebral ischemia vs stroke mimic). Secondary outcomes were 90-day stroke recurrence and 90-day composite outcome of stroke, myocardial infarction, or death. The association between presenting symptoms (focal vs nonfocal) and clinical diagnosis was also assessed. Research hypotheses were formulated after data collection. RESULTS: Of 1648 patients included, 770 (46.7%) were women, the median (interquartile range) age was 70 (59-80) years, 1509 patients (91.6%) underwent brain magnetic resonance imaging, and 1582 patients (96.0%) completed the 90-day follow-up. Women (522 of 770 [67.8%]) were less likely than men (674 of 878 [76.8%]) to receive a diagnosis of cerebral ischemia (adjusted risk ratio [aRR], 0.88; 95% CI, 0.82-0.95), but the 90-day stroke recurrence outcome (aRR, 0.90; 95% CI, 0.48-1.66) and 90-day composite outcome (aRR, 0.86; 95% CI, 0.54-1.32) were similar for men and women. No significant sex differences were found for presenting symptoms. Compared with patients with no focal neurologic symptoms, those with focal and nonfocal symptoms were more likely to receive a diagnosis of cerebral ischemia (aRR, 1.28; 95% CI, 1.15-1.39), but the risk was highest among patients with focal symptoms only (aRR, 1.45; 95% CI, 1.34-1.53). Sex did not modify these associations. CONCLUSIONS AND RELEVANCE: The results of the present study suggest that, despite similar presenting symptoms among men and women, women may be more likely to receive a diagnosis of stroke mimic, but they may not have a lower risk than men of subsequent vascular events, indicating potentially missed opportunities for prevention of vascular events among women.

Pulmonary Metastasectomy in Pediatric Solid Tumors.

Metastatic disease and the complications of treating metastatic disease are the primary causes of mortality in children with solid malignancies. Nearly 25% of children with solid tumors have metastatic disease at initial diagnosis and another 20% develop metastases during or after treatment. The most common location of these metastases is the lung. The role of surgery in metastatic disease depends greatly on the histology of the primary. In general, tumors that are refractory to adjuvant therapies are most appropriate for pulmonary metastasectomy. This article will summarize the indications for metastasectomy in pediatric solid tumors and discuss the ongoing debate over the technique of metastasectomy in osteosarcoma.

Efficacy of Nivolumab and Pembrolizumab in Patients With Advanced Non-Small-Cell Lung Cancer Needing Treatment Interruption Because of Adverse Events: A Retrospective Multicenter Analysis.

INTRODUCTION: The programmed death 1 antibodies (PD-1 Ab) nivolumab and pembrolizumab improve overall survival (OS) in advanced non-small-cell lung cancer (NSCLC). We evaluated the correlation between immune-related adverse events (irAE) and treatment interruption due to irAE on clinical efficacy of PD-1 Ab in advanced NSCLC. PATIENTS AND METHODS: Advanced NSCLC patients treated with PD-1 Ab between June 2015 to November 2017 at BC Cancer were identified. Demographic, tumor, treatment details, and frequency and grade (Common Terminology Criteria for Adverse Events, version 4.0) of irAE were abstracted from chart review. Kaplan-Meier curves of OS from initiation of PD-1 Ab were generated. Multivariable analysis with 6- and 12-week landmark analysis was performed by Cox proportional hazard regression models. RESULTS: In a cohort of 271 patients, irAEs were observed in 116 patients (42.8%). Nivolumab recipients developing colitis had lower OS compared to those who did not at the 6-week landmark (P = .010) and 12-week landmark (P = .072). For the entire cohort, 56 patients (20.7%) needed treatment interruption because of an irAE. Treatment interruption correlated with lower OS at the 6-week landmark (P = .005) and 12-week landmark (P = .008). Six-week landmark multivariable analysis identified Charlson Comorbidity Index score of 3 or higher, Eastern Cooperative Oncology Group Performance Status of 2 or higher, presence of liver metastases, and irAE greater than grade 2 versus no irAE to be associated with decreased OS (each P < .05). CONCLUSION: Treatment interruption due to irAE was associated with a lower median OS compared to continuous PD-1 Ab therapy. Shorter OS seen with severe irAE might reflect the need for improved physician education in irAE treatment algorithms.

Validation of a proteomic biomarker panel to diagnose minor-stroke and transient ischaemic attack: phase 2 of SpecTRA, a large scale translational study.

OBJECTIVE: To validate our previously developed 16 plasma-protein biomarker panel to differentiate between transient ischaemic attack (TIA) and non-cerebrovascular emergency department (ED) patients. METHOD: Two consecutive cohorts of ED patients prospectively enrolled at two urban medical centers into the second phase of SpecTRA study (training, cohort 2A, n = 575; test, cohort 2B, n = 528). Plasma samples were analyzed using liquid chromatography/multiple reaction monitoring-mass spectrometry. Logistic regression models which fit cohort 2A were validated on cohort 2B. RESULTS: Three of the panel proteins failed quality control and were removed from the panel. During validation, panel models did not outperform a simple motor/speech (M/S) deficit variable. Post-hoc analyses suggested the measured behaviour of L-selectin and coagulation factor V contributed to poor model performance. Removal of these proteins increased the external performance of a model containing the panel and the M/S variable. CONCLUSIONS: Univariate analyses suggest insulin-like growth factor-binding protein 3 and serum paraoxonase/lactonase 3 are reliable and reproducible biomarkers for TIA status. Logistic regression models indicated L-selectin, apolipoprotein B-100, coagulation factor IX, and thrombospondin-1 to be significant multivariate predictors of TIA. We discuss multivariate feature subset analyses as an exploratory technique to better understand a panel's full predictive potential.

Reducing time-to-unit among patients referred to an outpatient stroke assessment unit with a novel triage process: a prospective cohort study.

BACKGROUND: To evaluate the performance of a novel triage system for Transient Ischemic Attack (TIA) units built upon an existent clinical prediction rule (CPR) to reduce time to unit arrival, relative to the time of symptom onset, for true TIA and minor stroke patients. Differentiating between true and false TIA/minor stroke cases (mimics) is necessary for effective triage as medical intervention for true TIA/minor stroke is time-sensitive and TIA unit spots are a finite resource. METHODS: Prospective cohort study design utilizing patient referral data and TIA unit arrival times from a regional fast-track TIA unit on Vancouver Island, Canada, accepting referrals from emergency departments (ED) and general practice (GP). Historical referral cohort (N = 2942) from May 2013-Oct 2014 was triaged using the ABCD2 score; prospective referral cohort (N = 2929) from Nov 2014-Apr 2016 was triaged using the novel system. A retrospective survival curve analysis, censored at 28 days to unit arrival, was used to compare days to unit arrival from event date between cohort patients matched by low (0-3), moderate (4-5) and high (6-7) ABCD2 scores. RESULTS: Survival curve analysis indicated that using the novel triage system, prospectively referred TIA/minor stroke patients with low and moderate ABCD2 scores arrived at the unit 2 and 1 day earlier than matched historical patients, respectively. CONCLUSIONS: The novel triage process is associated with a reduction in time to unit arrival from symptom onset for referred true TIA/minor stroke patients with low and moderate ABCD2 scores.

Verification of a proteomic biomarker panel to diagnose minor stroke and transient ischaemic attack: phase 1 of SpecTRA, a large scale translational study.

OBJECTIVE: To derive a plasma biomarker protein panel from a list of 141 candidate proteins which can differentiate transient ischaemic attack (TIA)/minor stroke from non-cerebrovascular (mimic) conditions in emergency department (ED) settings. DESIGN: Prospective clinical study (#NCT03050099) with up to three timed blood draws no more than 36 h following symptom onset. Plasma samples analysed by multiple reaction monitoring-mass spectrometry (MRM-MS). PARTICIPANTS: Totally 545 participants suspected of TIA enrolled in the EDs of two urban medical centres. OUTCOMES: 90-day, neurologist-adjudicated diagnosis of TIA informed by clinical and radiological investigations. RESULTS: The final protein panel consists of 16 proteins whose patterns show differential abundance between TIA and mimic patients. Nine of the proteins were significant univariate predictors of TIA [odds ratio (95% confidence interval)]: L-selectin [0.726 (0.596-0.883)]; Insulin-like growth factor-binding protein 3 [0.727 (0.594-0.889)]; Coagulation factor X [0.740 (0.603-0.908)]; Serum paraoxonase/lactonase 3 [0.763 (0.630-0.924)]; Thrombospondin-1 [1.313 (1.081-1.595)]; Hyaluronan-binding protein 2 [0.776 (0.637-0.945)]; Heparin cofactor 2 [0.775 (0.634-0.947)]; Apolipoprotein B-100 [1.249 (1.037-1.503)]; and von Willebrand factor [1.256 (1.034-1.527)]. The scientific plausibility of the panel proteins is discussed. CONCLUSIONS: Our panel has the potential to assist ED physicians in distinguishing TIA from mimic patients.

Inhibition of fatty acid oxidation by etomoxir impairs NADPH production and increases reactive oxygen species resulting in ATP depletion and cell death in human glioblastoma cells.

Normal differentiated cells rely primarily on mitochondrial oxidative phosphorylation to produce adenosine triphosphate (ATP) to maintain their viability and functions by using three major bioenergetic fuels: glucose, glutamine and fatty acids. Many cancer cells, however, rely on aerobic glycolysis for their growth and survival, and recent studies indicate that some cancer cells depend on glutamine as well. This altered metabolism in cancers occurs through oncogene activation or loss of tumor suppressor genes in multiple signaling pathways, including the phosphoinositide 3-kinase and Myc pathways. Relatively little is known, however, about the role of fatty acids as a bioenergetic fuel in growth and survival of cancer cells. Here, we report that human glioblastoma SF188 cells oxidize fatty acids and that inhibition of fatty acid ß-oxidation by etomoxir, a carnitine palmitoyltransferase 1 inhibitor, markedly reduces cellular ATP levels and viability. We also found that inhibition of fatty acid oxidation controls the NADPH level. In the presence of reactive oxygen species scavenger tiron, however, ATP depletion is prevented without restoring fatty acid oxidation. This suggests that oxidative stress may lead to bioenergetic failure and cell death. Our work provides evidence that mitochondrial fatty acid oxidation may provide NADPH for defense against oxidative stress and prevent ATP loss and cell death.

Novel oncogenic mutations of CBL in human acute myeloid leukemia that activate growth and survival pathways depend on increased metabolism.

Acute myeloid leukemia (AML) is characterized by multiple mutagenic events that affect proliferation, survival, as well as differentiation. Recently, gain-of-function mutations in the α helical structure within the linker sequence of the E3 ubiquitin ligase CBL have been associated with AML. We identified four novel CBL mutations, including a point mutation (Y371H) and a putative splice site mutation in AML specimens. Characterization of these two CBL mutants revealed that coexpression with the receptor tyrosine kinases FLT3 (Fms-like tyrosine kinase 3) or KIT-induced ligand independent growth or ligand hyperresponsiveness, respectively. Growth of cells expressing mutant CBL required expression and kinase activity of FLT3. In addition to the CBL-dependent phosphorylation of FLT3 and CBL itself, transformation was associated with activation of Akt and STAT5 and required functional expression of the small GTPases Rho, Rac, and Cdc42. Furthermore, the mutations led to constitutively elevated intracellular reactive oxygen species levels, which is commonly linked to increased glucose metabolism in cancer cells. Inhibition of hexokinase with 2-deoxyglucose blocked the transforming activity of CBL mutants and reduced activation of signaling mechanisms. Overall, our data demonstrate that mutations of CBL alter cellular biology at multiple levels and require not only the activation of receptor proximal signaling events but also an increase in cellular glucose metabolism. Pathways that are activated by CBL gain-of-function mutations can be efficiently targeted by small molecule drugs.

Validity of information obtained from a method for estimating cancer costs from the perspective of patients and caregivers.

PURPOSE: We describe a method we developed for estimating cancer costs from the perspective of patients and caregivers and evidence supporting validity of estimates obtained. METHODS: To increase validity, interview questions were anchored to treatments; costs were divided into their components; most questions focused on facts; and the research team combined responses into cost estimates. Evidence for validity comes from a prospective study of breast cancer costs using this method. RESULTS: Estimates obtained using interview responses were similar to those from independent sources. Women reported being reimbursed $205 on average for prosthesis (government reimbursement =$200); paying $15.48 per night at cancer lodge (average rate =$17.52); receiving government illness insurance for 14.6 weeks at 53% of usual salary (governmental program covers 15 weeks at 55%). A priori hypotheses about relations of costs with other characteristics were also confirmed. For example, patients' weekly travel costs increased as a function of distance from the radiotherapy center, with patients living <25, 25-49 and ≥50 km away spending $54, $141 and $240, respectively (P<.0001); and the proportion of annual salary lost was 37% for self-employed workers compared to 18% for employees (P<.0001). CONCLUSIONS: Evidence to date supports the validity of estimates obtained using this method.

Conservation of helical bundle structure between the exocyst subunits.

BACKGROUND: The exocyst is a large hetero-octomeric protein complex required for regulating the targeting and fusion of secretory vesicles to the plasma membrane in eukaryotic cells. Although the sequence identity between the eight different exocyst subunits is less than 10%, structures of domains of four of the subunits revealed a similar helical bundle topology. Characterization of several of these subunits has been hindered by lack of soluble protein for biochemical and structural studies. METHODOLOGY/PRINCIPAL FINDINGS: Using advanced hidden Markov models combined with secondary structure predictions, we detect significant sequence similarity between each of the exocyst subunits, indicating that they all contain helical bundle structures. We corroborate these remote homology predictions by identifying and purifying a predicted domain of yeast Sec10p, a previously insoluble exocyst subunit. This domain is soluble and folded with approximately 60% alpha-helicity, in agreement with our predictions, and capable of interacting with several known Sec10p binding partners. CONCLUSIONS/SIGNIFICANCE: Although all eight of the exocyst subunits had been suggested to be composed of similar helical bundles, this has now been validated by our hidden Markov model structure predictions. In addition, these predictions identified protein domains within the exocyst subunits, resulting in creation and characterization of a soluble, folded domain of Sec10p.

Wage losses in the year after breast cancer: extent and determinants among Canadian women.

BACKGROUND: Wage losses after breast cancer may result in considerable financial burden. Their assessment is made more urgent because more women now participate in the workforce and because breast cancer is managed using multiple treatment modalities that could lead to long work absences. We evaluated wage losses, their determinants, and the associations between wage losses and changes for the worse in the family's financial situation among Canadian women over the first 12 months after diagnosis of early breast cancer. METHODS: We conducted a prospective cohort study among women with breast cancer from eight hospitals throughout the province of Quebec. Information that permitted the calculation of wage losses and information on potential determinants of wage losses were collected by three pretested telephone interviews conducted over the year following the start of treatment. Information on medical characteristics was obtained from medical records. The main outcome was the proportion of annual wages lost because of breast cancer. Multivariable analysis of variance using the general linear model was used to identify personal, medical, and employment characteristics associated with the proportion of wages lost. All statistical tests were two-sided. RESULTS: Among 962 eligible breast cancer patients, 800 completed all three interviews. Of these, 459 had a paying job during the month before diagnosis. On average, these working women lost 27% of their projected usual annual wages (median = 19%) after compensation received had been taken into account. Multivariable analysis showed that a higher percentage of lost wages was statistically significantly associated with a lower level of education (P(trend) = .0018), living 50 km or more from the hospital where surgery was performed (P = .070), lower social support (P = .012), having invasive disease (P = .086), receipt of chemotherapy (P < .001), self-employment (P < .001), shorter tenure in the job (P(trend) < .001), and part-time work (P < .001). CONCLUSION: Wage losses and their effects on financial situation constitute an important adverse consequence of breast cancer in Canada.