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The transmission line impedance of traveling-wave diodes can circumvent resistance-capacitance time constant limitations of metal-insulator-metal diodes in rectennas operating at optical frequencies. We performed three-dimensional simulations of a traveling-wave diode rectenna using a linear finite-element electromagnetic solver. We develop a method to analyze metal-insulator-metal traveling-wave rectennas by using the field profiles from the linear finite-element solver and accounting for the nonlinear current-voltage characteristics during postprocessing. The traveling-wave diode length produces resonance at half surface plasmon wavelength intervals. With optimized cross section and length parameters, we observe a peak system responsivity of 239 μ A / W and a detectivity of 5.7 × 10 4 Jones. [ABSTRACT FROM AUTHOR]

Background: An individual's genetic fingerprint is emerging as a pivotal predictor of numerous disease- and treatment-related factors. Single nucleotide polymorphisms (SNPs) in drug-metabolizing enzymes play key roles in an individual's exposure to a malignancy-associated risk, such as Aflatoxin B1 (AFB1)-induced hepatocellular carcinoma (HCC)., Aim: This study aimed at reviewing literature on the polymorphisms that exist in CYP enzymes and their possible link with susceptibility to AFB1-induced HCC., Materials & Methods: A set of keywords associated with the study subject of interest was used to search the Google Scholar and the PubMed database. The last ten years' worth of research projects were included in the results filter. The research involved HCC patients and any connection between polymorphic forms of CYP enzymes and their susceptibility to AFB1-induced HCC, including older but significant data., Results: Variations in CYP1A2 and CYP3A4 were reported to impact the rate and magnitude of AFB1 bio-activation, thus influencing an individual's vulnerability to develop HCC. In HCC patients, the activity of CYP isoforms varies, where increased activity has been reported with CYP2C9, CYP2D6, and CYP2E1, while CYP1A2, CYP2C8, and CYP2C19 exhibit decreased activity. CYP2D6*10 frequency has been discovered to differ considerably in HCC patients. Rs2740574 (an upstream polymorphism in CYP3A4 as detected in CYP3A4*1B) and rs776746 (which affects CYP3A5 RNA splicing), both of which influence CYP3A expression, thus impacting the variability of AFB1-epoxide adducts in HCC patients., Discussion: CYP1A2 is the primary enzyme accountable for the formation of harmful AFBO globally. CYP3A4, CYP3A5, CYP3A7, CYP2B7, and CYP3A3 are also implicated in the bio-activation of AFB1 to mutagenic metabolites. It is thought that CYP3A4 is the protein that interacts with AFB1 metabolism the most., Conclusion: Polymorphic variants of CYP enzymes have a functional impact on the susceptibility to AFB1-induced HCC. Outlining such variation and their implications may provide deeper insights into approaching HCC in a more personalized manner for guiding future risk-assessment, diagnosis, and treatment., (© 2024 Stichting European Society for Clinical Investigation Journal Foundation. Published by John Wiley & Sons Ltd.)

Objective: Suicide is the second leading cause of death in youth ten years old or older. Healthcare utilization prior to death by suicide is high in adults, but there is conflicting evidence in youth. The objective of this study was to compare healthcare utilization in youth who died by suicide to youth who died in a motor vehicle accident (MVC) to determine whether healthcare utilization is associated with death by suicide in youth., Methods: This retrospective case-control study used death records from Coroners/Medical Examiners (C/MEs) for children 11-17 years old who died by suicide (case) and MVC (control) between October 2013 and October 2018 were obtained. Data from the electronic medical record (EMR) at a healthcare system was reviewed. The primary outcome was healthcare utilization. Secondary outcomes included mental health diagnosis. Data was analyzed using Fisher's Exact Test and considered significant if p  < 0.05., Results: The analysis included 60 youth who died by suicide and 14 youth who died by MVC. Most decedents were male (68%) and white (80%). Mean age at death was 16 years old. Only 25 decedents had a corresponding record in the EMR, with no significant difference based on manner of death (35% suicide vs 29% MVC, p  = 0.8). Fourteen decedents had a known mental health diagnosis in their EMR with no difference based on manner of death ( p  = 0.5)., Conclusions: There was no difference in healthcare utilization or mental health diagnosis in youth who died by suicide compared to youth who died by MVC. Strict reliance on both of these factors when considering youth who may be at risk of suicide is inadequate. Expanding universal suicide screening to other settings, including schools or primary care, can help identify youth at risk for suicide and may prevent unnecessary deaths.HIGHLIGHTSLittle is known regarding the healthcare utilization of youth who died by suicide prior to their death.This study uses a case-control design to investigation healthcare utilization of youth who died by suicide versus youth who died in a motor vehicle crash.We did not find a significant difference in healthcare utilization between cases and controls. These findings suggest that non-clinical interventions would be useful in detecting suicide risk.

Background: Ibrutinib is a tyrosine kinase inhibitor most commonly associated with atrial fibrillation. However, additional cardiotoxicities have been identified, including accelerated hypertension. The incidence and risk factors of new or worsening hypertension following ibrutinib treatment are not as well known., Methods: We conducted a retrospective study of 144 patients diagnosed with B cell malignancies treated with ibrutinib (n=93) versus conventional chemoimmunotherapy (n=51) and evaluated their effects on blood pressure at 1, 2, 3 and 6 months after treatment initiation. Descriptive statistics were used to compare baseline characteristics for each treatment group. Fisher's exact test was used to identify covariates significantly associated with the development of hypertension. Repeated measures analyses were conducted to analyse longitudinal blood pressure changes., Results: Both treatments had similar prevalence of baseline hypertension at 63.4% and 66.7%, respectively. There were no differences between treatments by age, sex and baseline cardiac comorbidities. Both systolic and diastolic blood pressure significantly increased over time with ibrutinib compared with baseline, whereas conventional chemoimmunotherapy was not associated with significant changes in blood pressure. Baseline hypertensive status did not affect the degree of blood pressure change over time. A significant increase in systolic blood pressure (defined as more than 10 mm Hg) was noted for ibrutinib (36.6%) compared with conventional chemoimmunotherapy (7.9%) at 1 month after treatment initiation. Despite being hypertensive at follow-up, 61.2% of patients who were treated with ibrutinib did not receive adequate blood pressure management (increase or addition of blood pressure medications). Within the ibrutinib group, of patients who developed more than 20 mm Hg increase in systolic blood pressure, only 52.9% had hypertension management changes., Conclusions: Ibrutinib is associated with the development of hypertension and worsening of blood pressure. Cardiologists and oncologists must be aware of this cardiotoxicity to allow timely management of blood pressure elevations., Competing Interests: Competing interests: MF is advisor/consultant for Takeda and Abbott and received research grant from Medtronic. JP-I is investigator for Novartis and Ariad; consultant/advisor for Novartis, Bristol-Myers Squibb and Ariad; and received consulting/speakers bureau fees from Janssen and Pharmacyclics. The rest of the authors have nothing to disclose., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: Women with breast cancer (BCA) and cardiovascular disease (CVD) risk factors are at increased risk of developing cardiovascular complications when exposed to potentially cardiotoxic cancer therapy. The benefit of aggressive CVD risk factor modification to reduce adverse treatment-related psychologic and biologic effects is not well established., Methods: Using a single group pre-test, post-test design, 33 women with BCA receiving anthracycline and/or trastuzumab therapy participated in a 6-month comprehensive CVD risk reduction program involving formal cardio-oncology evaluation along with regular motivational counseling for improved nutrition and physical activity. Study parameters were assessed at baseline and 6 months with paired t-tests used to evaluate changes after the intervention., Results: The mental component summary score assessed by SF-36 V2 improved significantly after program completion (45.0 to 48.8, effect size 0.37, p = 0.017), however the physical component summary score declined (46.2 to 40.9, effect size - 0.53, p = 0.004). Despite this decline in perceived physical health, markers of health-related fitness and nutritional status were maintained or improved. Systolic and diastolic blood pressure also improved after the intervention (136.7 to 124.1 mmHg, p = 0.001 and 84.0 to 78.7 mmHg, p = 0.031, respectively). No significant change in resting heart rate, body mass index, lipids, hemoglobin A1C, or left ventricular ejection fraction was observed., Conclusions: Patient-reported mental health improved significantly in women with BCA enrolled in a comprehensive CVD risk reduction program despite exposure to potentially cardiotoxic therapies. This study provides preliminary data for future randomized controlled trials evaluating the effects CVD risk reduction program in high-risk breast cancer cohorts.

Erenumab is a monoclonal antibody that mediates calcitonin-gene-related peptide (CGRP), a pro-inflammatory polypeptide implicated in migraine pathology, by targeting its receptor. To date, no clinical trial has evaluated combination therapy with both erenumab and onabotulinumtoxinA therapy for the treatment of chronic migraine. We conducted a retrospective chart review of 78 patients to investigate if the addition of erenumab to patients with chronic migraines receiving onabotulinumtoxinA had a decrease in their total monthly headache days (MHDs) and monthly migraine days (MMD). At baseline, while on onabotulinumtoxinA, mean MHDs were 22.5 ± 8.7 and mean MMDs were 15.8 ± 8.3, and 65 patients (83.3%) failed at least three preventative therapies. Our results demonstrated a significant reduction in MHDs and MMDs at 30- (-6.8 MHDs; p < 0.001, -7.0 MMDs; p < 0.001), 60- (-7.2 MHDs; p < 0.001, -6.7 MMDs; p < 0.001), and 90 days (-8.1 MHDs; p < 0.001, -7.4 MMDs; p < 0.001). Thus, the results of this study suggest favorable outcomes with the addition of erenumab to patients who were still suffering while receiving onabotulinumtoxinA therapy. Additional investigation is needed to determine if erenumab in combination with onabotulinumtoxinA has an enhanced effect on the modulation of CGRP release from peripheral unmyelinated C fibers while also blocking CGRP receptors in the myelinated A-delta fibers.

Background: Bullous pemphigoid (BP) is a chronic immune-mediated vesiculobullous disorder. Recently, several reports have described dipeptidyl peptidase-4 inhibitors, also known as gliptins, as causative agents for drug-induced BP., Objective: To report and describe clinical and histologic characteristics of 10 cases of gliptin-induced BP., Results: We identified 10 patients with gliptin-induced BP. Nine were secondary to linagliptin, and 1 case was attributed to sitagliptin. All patients showed significant improvement after withdrawal of gliptin medications and proper medical treatment. There has been no evidence of relapse after 4 months of follow-up., Conclusion: This report supports the proposed association between gliptins and BP. Physicians should be aware of this potential adverse effect, as gliptin-induced BP can be reversible once identified and the responsible medication is stopped. Early withdrawal of the offending drug and proper treatment can lead to rapid improvement and reduced morbidity.

Background: Myocarditis is a highly morbid complication of immune checkpoint inhibitor (ICI) use that remains inadequately characterized. The QRS duration and the QTc interval are standardized electrocardiographic measures that are prolonged in other cardiac conditions; however, there are no data on their utility in ICI myocarditis., Methods: From an international registry, ECG parameters were compared between 140 myocarditis cases and 179 controls across multiple time points (pre-ICI, on ICI prior to myocarditis, and at the time of myocarditis). The association between ECG values and major adverse cardiac events (MACE) was also tested., Results: Both the QRS duration and QTc interval were similar between cases and controls prior to myocarditis. When compared with controls on an ICI (93±19 ms) or to baseline prior to myocarditis (97±19 ms), the QRS duration prolonged with myocarditis (110±22 ms, p<0.001 and p=0.009, respectively). In contrast, the QTc interval at the time of myocarditis (435±39 ms) was not increased compared with pre-myocarditis baseline (422±27 ms, p=0.42). A prolonged QRS duration conferred an increased risk of subsequent MACE (HR 3.28, 95% CI 1.98 to 5.62, p<0.001). After adjustment, each 10 ms increase in the QRS duration conferred a 1.3-fold increase in the odds of MACE (95% CI 1.07 to 1.61, p=0.011). Conversely, there was no association between the QTc interval and MACE among men (HR 1.33, 95% CI 0.70 to 2.53, p=0.38) or women (HR 1.48, 95% CI 0.61 to 3.58, p=0.39)., Conclusions: The QRS duration is increased in ICI myocarditis and is associated with increased MACE risk. Use of this widely available ECG parameter may aid in ICI myocarditis diagnosis and risk-stratification., Competing Interests: Competing interests: SSM has received consultancy fees from OMR Globus, Alpha Detail, and Opinion Research Team. RS has been a consultant to Merck and Novartis. LH has received consultancy, advisory board, and speaker fees from MSD, BMS, Roche, Novartis, Amgen, and Curevac. LZu has been a consultant to Merck. JG has received research support from Amgen. AN has received research support from Amgen and has been a consultant for Takeda Oncology and AstraZeneca. TGN has received advisory fees from Parexel, AbbVie, H3-Biomedicine, Aprea Therapeutics, BMS, and Intrinsic Imaging. TGN has received grant funding from AstraZeneca., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Biologic drugs are increasingly being prescribed for the treatment of psoriasis. Very little information is available in the literature regarding potential drug interactions with these medications. This paper serves as a guide for prescribers to be aware of possible interactions between biologic drugs approved for the treatment of psoriasis in North America and concomitant therapies., Objective: To provide an overview of reported drug interactions between biologic drugs and concomitant therapies., Methods: Reports of potential drug interactions were compiled through a search of Micromedex, drug monographs (Canadian, American, and European), as well as a PubMed search of each biologic drug with the term "drug interaction.", Conclusion: Generally, caution should be exercised when multiple immunosuppressive therapies are prescribed due to increased risk of infection. However, this is more the result of a synergistic effect as opposed to a true drug interaction. There have been cases where multiple biologic therapies have been concomitantly used without adverse events, as their mechanisms involved different pathways. The sources used to compile this guide were often comprised of low levels of evidence, reinforcing the idea that further studies are required to better direct prescribers.

Background: Atrial fibrillation (AF) is a common cardiovascular complication affecting patients with cancer, but management strategies are not well established., Objectives: The purpose of this retrospective cohort study was to evaluate cross-sectional patterns of anticoagulation (AC) use in patients with cancer with AF or atrial flutter (AFL) on the basis of their risk for stroke and bleeding., Methods: Patients with cancer and electrocardiograms showing AF or AFL performed at Moffitt Cancer Center in either the inpatient or outpatient setting were included in this retrospective analysis. We described percentages of AC prescription by stroke and bleeding risk, as determined by individual CHA 2 DS 2 -VASc and HAS-BLED scores, respectively. Multivariable logistic regression evaluated clinical variables independently associated with anticoagulant prescription., Results: The prevalence of electrocardiography-documented AF or AFL was 4.8% (n = 472). The mean CHA 2 DS 2 -VASc score was 2.8 ± 1.4. Among patients with CHA 2 DS 2 -VASc scores ≥2 and HAS-BLED scores <3, 44.3% did not receive AC, and of these, only 18.3% had platelet values <50,000/μl. In multivariable analysis, older age, hypertension, prior stroke, and history of venous thromboembolism were each directly associated with AC use, while current chemotherapy use, prior bleeding, renal disease, and thrombocytopenia were each inversely associated with AC use., Conclusions: Nearly one-half of patients with cancer, the majority with normal platelet counts, had an elevated risk for stroke but did not receive AC. In addition to known predictors, current chemotherapy use was independently associated with a lower odds of AC use. This study highlights the need to improve the application of AF treatment algorithms to cancer populations., Competing Interests: Dr. Fradley has received a research grant from Medtronic; and has received consulting fees from Abbott and Takeda. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2020 The Authors.)

Introduction: Pembrolizumab is an immune checkpoint inhibitor targeting the programmed death receptor with clinical effect on multiple malignancies including sarcoma. Associated cardio-toxicities include myocarditis, cardiomyopathy, heart failure, and arrhythmias. Although in most cases of immune checkpoint inhibitor cardiotoxicity the offending agent is discontinued, we report a case of successful and safe re-challenge with a checkpoint inhibitor in a patient with mild myocarditis., Case Report: We describe a 37-year-old female with alveolar soft part sarcoma, metastatic to the lungs on cycle 13 of pembrolizumab who presented with dyspnea, cough, and vague chest discomfort. Telemetry showed bigeminal bradycardia that transitioned to self-terminating torsades de pointes. Cardiac MRI showed subtle patchy T2 signal increase within the left ventricular septum without late gadolinium uptake, suggesting mild focal myocarditis.Management and outcome: The patient was started on a steroid taper without additional arrhythmias. We have re-challenged the patient who safely tolerated re-challenge with pembrolizumab despite an episode of torsades de pointes and documented myocarditis. She continues to receive pembrolizumab at seven months after the initial event without further cardiovascular events., Discussion: To the best of our knowledge, this is the first reported case of successful re-challenge of pembrolizumab after an episode of myocarditis. In patients with mild myocarditis and no evidence of left ventricular dysfunction, re-challenge may be a viable option. However, close monitoring for the development of heart failure, cardiomyopathy, or serious arrhythmias is necessary to ensure patient safety.

Aims: Myocarditis is a potentially fatal complication of immune checkpoint inhibitors (ICI). Sparse data exist on the use of cardiovascular magnetic resonance (CMR) in ICI-associated myocarditis. In this study, the CMR characteristics and the association between CMR features and cardiovascular events among patients with ICI-associated myocarditis are presented., Methods and Results: From an international registry of patients with ICI-associated myocarditis, clinical, CMR, and histopathological findings were collected. Major adverse cardiovascular events (MACE) were a composite of cardiovascular death, cardiogenic shock, cardiac arrest, and complete heart block. In 103 patients diagnosed with ICI-associated myocarditis who had a CMR, the mean left ventricular ejection fraction (LVEF) was 50%, and 61% of patients had an LVEF ≥50%. Late gadolinium enhancement (LGE) was present in 48% overall, 55% of the reduced EF, and 43% of the preserved EF cohort. Elevated T2-weighted short tau inversion recovery (STIR) was present in 28% overall, 30% of the reduced EF, and 26% of the preserved EF cohort. The presence of LGE increased from 21.6%, when CMR was performed within 4 days of admission to 72.0% when CMR was performed on Day 4 of admission or later. Fifty-six patients had cardiac pathology. Late gadolinium enhancement was present in 35% of patients with pathological fibrosis and elevated T2-weighted STIR signal was present in 26% with a lymphocytic infiltration. Forty-one patients (40%) had MACE over a follow-up time of 5 months. The presence of LGE, LGE pattern, or elevated T2-weighted STIR were not associated with MACE., Conclusion: These data suggest caution in reliance on LGE or a qualitative T2-STIR-only approach for the exclusion of ICI-associated myocarditis., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2020. For permissions, please email: journals.permissions@oup.com.)

There is increasing evidence that rates of atrial arrhythmias (AA), specifically atrial fibrillation and flutter are elevated in patients treated with the tyrosine kinase inhibitor, ibrutinib; however, the exact risk of ibrutinib-associated AA is not definitively established. We conducted a retrospective study of 137 patients diagnosed with B-cell malignancies treated with ibrutinib compared with 106 patients treated with chemotherapy for the same cancers in order to quantify the rates and risk of AA in a "real-world" sample of cancer patients. Fisher's exact test was used to evaluate for any statistically significant differences between groups. Logistic regression was used to generate odds ratios, adjusting for potential confounders. Incidence of AA was 14% (n = 17) in ibrutinib-treated patients compared with 3% (n = 3) in patients treated with chemotherapy (p = 0.009). Ibrutinib-treated patients were significantly older (mean age 67 vs 63 years, p = 0.003); however, there were no other significant differences in baseline characteristics. Ibrutinib use, age, hypertension, and previous use of ACE inhibitors, angiotensin receptor blocker use, β blocker use, and aspirin use were independently associated with incident arrhythmias. In multivariable analysis, patients treated with ibrutinib were associated with a 5-fold increased risk of developing AA (odds ratio = 5.18, 95% confidence interval 1.42 to 18.89). In conclusion, the rates and risk of AA are higher in patients treated with ibrutinib compared with chemotherapy, and this study provides strong evidence that ibrutinib itself is an independent risk factor for the development of incident AA., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Aims: Heart failure (HF) outcomes continue to improve with widespread use of new therapies. Concurrently, cancer survival has dramatically improved. Yet whether cancer patients share similar strategies and outcomes of inpatient HF treatment to those without HF is unknown. We sought to assess the contemporary impacts of cancer on inpatient HF outcomes over time., Methods and Results: The retrospective National Inpatient Sample (2003-15) and National Readmissions Database (2013-14) registries were queried for adults admitted for HF and stratified for cancer status, excluding cases of metastatic disease. Temporal trends in HF admissions, hospital charge rates, length of hospitalization, HF-related procedure utilization, in-hospital mortality, and hospital readmissions were analysed. Over 13 years of follow-up, there were 12 769 077 HF admissions (mean age 73 years, 50.8% female, 30.8% non-White), among which 1 413 287 (11%) had a co-morbid cancer diagnosis. Cancer patients were older, were predominantly male, and tended to be smokers. Over time, HF admission rates among cancer patients increased, despite a concurrent decrease among patients without cancer (P < 0.0001). After propensity matching, in-hospital mortality was significantly higher among cancer HF patients (5.1% vs. 2.9%, P < 0.0001). Additionally, HF-related procedure utilization was disproportionately lower among cancer patients (0.30 vs. 0.35 procedures/HF hospitalization, P < 0.001); the presence of cancer was associated with increased costs, length of hospitalizations, and all-cause readmissions, but fewer HF readmissions (P < 0.0001, each)., Conclusions: While the incidence of HF hospitalizations has increased among cancer patients, they do not appear to share the same rates of advanced HF care, readmissions trends, or reductions in in-hospital mortality. Future studies targeting modifiable factors related to these differences are needed., (© 2019 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of the European Society of Cardiology.)

Background: Influenza vaccination (FV) is recommended for patients with cancer. Recent data suggested that the administration of the FV was associated with an increase in immune-related adverse events (irAEs) among patients on immune checkpoint inhibitors (ICIs). Myocarditis is an uncommon but serious complication of ICIs and may also result from infection with influenza. There are no data testing the relationship between FV and the development of myocarditis on ICIs., Methods: Patients on ICIs who developed myocarditis (n = 101) (cases) were compared to ICI-treated patients (n = 201) without myocarditis (controls). A patient was defined as having the FV if they were administered the FV from 6 months prior to start of ICI to anytime during ICI therapy. Alternate thresholds for FV status were also tested. The primary comparison of interest was the rate of FV between cases and controls. Patients with myocarditis were followed for major adverse cardiac events (MACE), defined as the composite of cardiogenic shock, cardiac arrest, hemodynamically significant complete heart block and cardiovascular death., Results: The FV was administered to 25% of the myocarditis cases compared to 40% of the non-myocarditis ICI-treated controls (p = 0.01). Similar findings of lower rates of FV administration were noted among myocarditis cases when alternate thresholds were tested. Among the myocarditis cases, those who were vaccinated had 3-fold lower troponin levels when compared to unvaccinated cases (FV vs. No FV: 0.12 [0.02, 0.47] vs. 0.40 [0.11, 1.26] ng/ml, p = 0.02). Within myocarditis cases, those administered the FV also had a lower rate of other irAEs when compared to unvaccinated cases (36 vs. 55% p = 0.10) including lower rates of pneumonitis (12 vs. 36%, p = 0.03). During follow-up (175 [IQR 89, 363] days), 47% of myocarditis cases experienced a MACE. Myocarditis cases who received the FV were at a lower risk of cumulative MACE when compared to unvaccinated cases (24 vs. 59%, p = 0.002)., Conclusion: The rate of FV among ICI-related myocarditis cases was lower than controls on ICIs who did not develop myocarditis. In those who developed myocarditis related to an ICI, there was less myocardial injury and a lower risk of MACE among those who were administered the FV.

There have been significant advances in the field of oncology leading to improved survival as a result of novel targeted and immunotherapies. Despite these improved outcomes, there is increased recognition of cardiotoxicities associated with these therapies that can lead to significant morbidity and mortality. As such, the field of cardio-oncology has seen significant growth over the last several years. In this review, we discuss recent advances in the field of cardio-oncology and provide a detailed discussion of the cardiovascular complications associated with novel cancer therapeutics including tyrosine kinase inhibitors, proteasome inhibitors, histone deacetylase inhibitors, CDK4/6 inhibitors and immunotherapies., (Copyright © 2018. Published by Elsevier Inc.)

We have identified a novel form of the full-length E2F-3 protein that we term E2F-3B. In contrast to full-length E2F-3, which is expressed only at the G1/S boundary, E2F-3B is detected throughout the cell cycle with peak levels in GO where it is associated with Rb. Transfection and in vitro translation experiments demonstrate that a protein identical to E2F-3B in size and iso-electric point is produced from the E2F-3 mRNA via the use of an alternative translational start site. This alternative initiation codon was mapped by mutagenesis to codon 102, an ACG codon. Mutation of the ACG codon at position 102 abolished E2F-3B expression, whereas the conversion of ACG 102 to a consensus ATG led to the expression of a protein indistinguishable from E2F-3B. Given these results, E2F-3B is missing 101 N-terminal amino acids relative to full-length E2F-3. This region includes a moderately conserved sequence of unknown function that is present only in the growth-promoting E2F family members, including E2F-1, 2 and full-length E2F-3. These observations make E2F-3B the first example of an E2F gene giving rise to two different protein species and also suggest that E2F-3 and E2F-3B may have opposing roles in cell cycle control.