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PURPOSE: The objective of this study was to describe the incidence of grade 3/4 neutropenia, patterns of chemotherapy treatment, and granulocyte colony-stimulating factor (G-CSF) use patterns among patients with non-Hodgkin's lymphoma (NHL)<65 and ≥65 years. METHODS: This retrospective, observational study included adult patients with NHL who received cyclophosphamide, doxorubicin, vincristine, and prednisone±rituximab (CHOP±R) from January 2006 to June 2010. RESULTS: A total of 1,579 patients were included, with 54.1%<65 years and 45.9%≥65 years. Most received CHOP-R on a Q3W schedule. Among patients<65 years, the incidence of grade 3/4 neutropenia was 52.3%, the mean relative dose intensity (RDI) was 80.4%, and the incidences of dose delays and reductions were 26.5 and 9.6%, respectively. Among patients≥65 years, the incidence of grade 3/4 neutropenia was 63.2%, the mean RDI was 73.9%, and the incidences of dose delays and reductions were 24.6 and 24.9%, respectively. Most patients (86.9%) received G-CSF. Among patients<65 years, 71.9, 17.4, and 10.7% first received G-CSF as primary prophylaxis, secondary prophylaxis, or treatment, respectively. Among patients≥65 years, 80.1, 11.6, and 8.3% first received G-CSF as primary prophylaxis, secondary prophylaxis, or treatment, respectively. CONCLUSIONS: Chemotherapy regimens and schedules were similar among age groups. Grade 3/4 neutropenia, reduced RDI, and dose delays were common in both age groups, though patients≥65 years had a higher incidence of dose reductions. In spite of these similarities, patients<65 years were less likely to receive primary prophylactic G-CSF. Thus, careful assessment of neutropenia risk factors is needed across age groups to determine appropriate G-CSF use and support planned chemotherapy.
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Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Linfoma não Hodgkin/sangue , Linfoma não Hodgkin/tratamento farmacológico , Neutropenia/induzido quimicamente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais Murinos/administração & dosagem , Anticorpos Monoclonais Murinos/efeitos adversos , Ciclofosfamida/administração & dosagem , Ciclofosfamida/efeitos adversos , Relação Dose-Resposta a Droga , Doxorrubicina/administração & dosagem , Doxorrubicina/efeitos adversos , Feminino , Fator Estimulador de Colônias de Granulócitos/administração & dosagem , Humanos , Masculino , Pessoa de Meia-Idade , Neutropenia/tratamento farmacológico , Neutropenia/prevenção & controle , Prednisona/administração & dosagem , Prednisona/efeitos adversos , Estudos Retrospectivos , Fatores de Risco , Rituximab , Vincristina/administração & dosagem , Vincristina/efeitos adversos , Adulto JovemRESUMO
Background: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a chronic, multifaceted disease that affects millions globally. Despite its significant impact, the disease's etiology remains poorly understood, and symptom heterogeneity poses challenges for diagnosis and treatment. Joint hypermobility, commonly seen in hypermobile Ehlers-Danlos Syndrome (hEDS), has been observed in ME/CFS patients but its prevalence and clinical significance within this population are not well-characterized. Objective: To compare the characteristics of ME/CFS patients with and without joint hypermobility (JH+ and JH-) as assessed using the Beighton scoring system, and to explore whether JH+ ME/CFS patients exhibit distinct disease characteristics, comorbidities, and health-related quality of life (HRQOL). Methods: The study used cross-sectional, self-reported data from 815 participants of the You + ME Registry. Participants were categorized as JH+ or JH- based on self-assessed Beighton scores and compared across demographics, comorbidities, family history, and symptoms. HRQOL was assessed using the Short Form-36 RAND survey and Karnofsky Performance Status. Results: 15.5% (N = 126) of participants were classified as JH+. JH+ participants were more likely to be female, report Ehlers-Danlos Syndrome (EDS), Postural Orthostatic Tachycardia Syndrome (POTS), and a family history of EDS. They experienced worse HRQOL, particularly in physical functioning and pain, and a higher number of autonomic, neurocognitive, headache, gut, and musculoskeletal symptoms. Sensitivity analysis suggested that ME/CFS with concurrent JH+ and EDS was associated with more severe symptoms and greater functional impairment. Conclusion: ME/CFS patients with joint hypermobility, particularly those with EDS, demonstrate distinct clinical characteristics, including more severe symptomatology and reduced HRQOL. These findings highlight the need for comprehensive clinical assessments of ME/CFS patients with joint hypermobility. Understanding these relationships could aid in subgroup identification, improving diagnosis, and informing targeted therapeutic approaches. Further research is warranted to explore these associations and their implications for clinical practice.
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Early-stage breast cancer (ESBC) is commonly treated with myelosuppressive chemotherapy, and maintaining full-dose chemotherapy on the planned schedule is associated with improved patient outcome. Retrospective analysis of patients with ESBC treated from 1997 to 2000 showed that 56 % of patients received a relative dose intensity (RDI) <85 % (Lyman et al., J Clin Oncol 21(24):4524-4531, 2003). To determine current practice, we evaluated treatment patterns at 24 US community- and hospital-based oncology practices, 79 % of which participated in the previous study. Data were abstracted from medical records of 532 patients with surgically resected ESBC (stage I-IIIa) treated from 2007 to 2009, who were ≥18 years old and had completed ≥1 cycle of one of the following regimens: docetaxel + cyclophosphamide (TC); doxorubicin + cyclophosphamide (AC); AC followed by paclitaxel (AC-T); docetaxel + carboplatin + trastuzumab (TCH); or docetaxel + doxorubicin + cyclophosphamide (TAC). Endpoints included RDI, dose delays, dose reductions, grade 3/4 neutropenia, febrile neutropenia (FN), FN-related hospitalization, granulocyte colony-stimulating factor (G-CSF) use, and antimicrobial use. In this study, TC was the most common chemotherapy regimen (42 %), and taxane-based chemotherapy regimens were more common relative to the previously published results (89 vs <4 %). Overall, 83.8 % of patients received an RDI ≥85 %, an improvement over the previous study where 44.5 % received an RDI ≥85 %. Other changes seen between this and the previous study included a lower incidence of dose delays (16 vs 25 %) and dose reductions (21 vs 37 %) and increased use of primary prophylactic G-CSF (76 vs ~3 %). Here, 40 % of patients had grade 3/4 neutropenia, 3 % had FN, 2 % had an FN-related hospitalization, and 30 % received antimicrobial therapy; these measures were not available in the previously published results. Though RDI was higher here than in the previous study, 16.2 % of patients still received an RDI <85 %. Understanding factors that contribute to reduced RDI may further improve chemotherapy delivery, and ultimately, patient outcomes.
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Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Neoplasias da Mama/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Neoplasias da Mama/cirurgia , Ciclofosfamida/administração & dosagem , Docetaxel , Doxorrubicina/administração & dosagem , Esquema de Medicação , Neutropenia Febril/induzido quimicamente , Feminino , Filgrastim , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Humanos , Pessoa de Meia-Idade , Análise Multivariada , Paclitaxel/administração & dosagem , Polietilenoglicóis , Proteínas Recombinantes/uso terapêutico , Estudos Retrospectivos , Taxoides/administração & dosagemRESUMO
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BACKGROUND: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a chronic, complex, heterogeneous disease that affects millions and lacks both diagnostics and treatments. Big data, or the collection of vast quantities of data that can be mined for information, have transformed the understanding of many complex illnesses, such as cancer and multiple sclerosis, by dissecting heterogeneity, identifying subtypes, and enabling the development of personalized treatments. It is possible that big data can reveal the same for ME/CFS. OBJECTIVE: This study aims to describe the protocol for the You + ME Registry, present preliminary results related to participant enrollment and satisfaction, and discuss the limitations of the registry as well as next steps. METHODS: We developed and launched the You + ME Registry to collect longitudinal health data from people with ME/CFS, people with long COVID (LC), and control volunteers using rigorous protocols designed to harmonize with other groups collecting data from similar groups of people. RESULTS: As of September 30, 2021, the You + ME Registry had over 4200 geographically diverse participants (3033/4339, 69.9%, people with ME/CFS; 833/4339, 19.2%, post-COVID-19 people; and 473/4339, 10.9%, control volunteers), with an average of 72 new people registered every week. It has qualified as "great" using a net promotor score, indicating registrants are likely to recommend the registry to a friend. Analyses of collected data are currently underway, and preliminary findings are expected in the near future. CONCLUSIONS: The You + ME Registry is an invaluable resource because it integrates with a symptom-tracking app, as well as a biorepository, to provide a robust and rich data set that is available to qualified researchers. Accordingly, it facilitates collaboration that may ultimately uncover causes and help accelerate the development of therapies. TRIAL REGISTRATION: ClinicalTrials.gov NCT04806620; https://clinicaltrials.gov/ct2/show/NCT04806620. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/36798.
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Background: The 2016 President's Cancer Panel called for projects focusing on improving cancer symptom management using connected health technologies (broadband and telecommunications). However, rural communities, like those in Appalachia, may experience a "double burden" of high cancer rates and lower rates of broadband access and adoption necessary for connected health solutions. Purpose: To better understand the current landscape of connected health in the management of cancer symptoms in rural America. Methods: A literature search was conducted using four academic databases (PubMed, CINAHL, MEDLINE, and PsycINFO) to locate articles published from 2010 to 2019 relevant to connected cancer symptom management in rural America. Text screening was conducted to identify relevant publications. Results: Among 17 reviewed studies, four were conducted using a randomized controlled trial; the remainder were formative in design or small pilot projects. Five studies engaged stakeholders from rural communities in designing solutions. Most commonly studied symptoms were psychological/emotional symptoms, followed by physical symptoms, particularly pain. Technologies used were primarily telephone-based; few were Internet-enabled video conferencing or web-based. Advanced mobile and Internet-based approaches were generally in the development phase. Overall, both rural patients and healthcare providers reported high acceptance, usage, and satisfaction of connected health technologies. Ten of the 17 studies reported improved symptom management outcomes. Methodological challenges that limited the interpretation of the findings were summarized. Implications: The review identified a need to engage rural stakeholders to develop and test connected cancer symptom management solutions that are based on advanced mobile and broadband Internet technologies.
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BACKGROUND: Pegfilgrastim's role in reducing the risk of febrile neutropenia (FN) in patients with colorectal cancer (CRC) receiving chemotherapy plus bevacizumab was not previously evaluated in a prospective study. The present phase III, double-blind trial evaluated the efficacy of pegfilgrastim versus placebo in reducing the incidence of grade 3/4 FN in patients with advanced CRC receiving bevacizumab combined with first-line chemotherapy (FOLFOX [leucovorin, 5-fluorouracil, oxaliplatin] or FOLFIRI [leucovorin, 5-fluorouracil, irinotecan]). PATIENTS AND METHODS: Patients aged ≥ 18 years with locally advanced or metastatic CRC were randomized 1:1 to placebo or 6 mg of pegfilgrastim â¼24 hours after receiving chemotherapy plus bevacizumab every 14 days. The study treatment period included 4 cycles, but patients could continue treatment for ≤ 60 months. The primary endpoint was incidence of grade 3/4 FN in the first 4 cycles. The secondary endpoints included the objective response rate (ORR), overall survival, and progression-free survival, analyzed at the end of the long-term follow-up period. RESULTS: A total of 845 patients were randomized from November 2009 to January 2012 (422, pegfilgrastim; 423, placebo). Pegfilgrastim significantly reduced the incidence of grade 3/4 FN in the first 4 treatment cycles (pegfilgrastim, 2.4%; 95% confidence interval [CI], 1.1%-4.3%; placebo, 5.7%; 95% CI, 3.7%-8.3%; odds ratio [OR], 0.41; P = .014). No significant differences were observed between the 2 arms in ORR (OR, 1.15; P = .330), overall survival (hazard ratio, 0.94; P = .440), and progression-free survival (hazard ratio, 0.93; P = .300). CONCLUSION: Pegfilgrastim reduced the FN incidence in patients with advanced CRC receiving chemotherapy and bevacizumab. Administration of pegfilgrastim was tolerable and did not negatively affect the tumor response or survival in this patient population.
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Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Neoplasias Colorretais/tratamento farmacológico , Neutropenia Febril/prevenção & controle , Filgrastim/administração & dosagem , Polietilenoglicóis/administração & dosagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Bevacizumab/administração & dosagem , Camptotecina/administração & dosagem , Camptotecina/efeitos adversos , Camptotecina/análogos & derivados , Neoplasias Colorretais/patologia , Intervalo Livre de Doença , Método Duplo-Cego , Neutropenia Febril/induzido quimicamente , Neutropenia Febril/epidemiologia , Feminino , Fluoruracila/administração & dosagem , Fluoruracila/efeitos adversos , Seguimentos , Humanos , Incidência , Leucovorina/administração & dosagem , Leucovorina/efeitos adversos , Masculino , Pessoa de Meia-Idade , Metástase Neoplásica , Compostos Organoplatínicos/administração & dosagem , Compostos Organoplatínicos/efeitos adversos , Modelos de Riscos Proporcionais , Estudos Prospectivos , Taxa de Sobrevida , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Adulto JovemRESUMO
Realization that many tumor suppressor genes are silenced by epigenetic mechanisms has stimulated the discovery of novel tumor suppressor genes. We used a variety of research tools to search for genes that are epigenetically silenced in human endometrial cancers. Changes in global gene expression of the endometrial cancer cell line Ishikawa was analyzed after treatment with the demethylating agent 5-aza-2'-deoxycytidine combined with the histone deacetylase inhibitor suberoylanilide bishydroxamide. By screening over 22,000 genes, candidate tumor suppressor genes were identified. Additional microarray analysis and real-time reverse transcription-PCR of normal and cancerous endometrial samples and search for CpG islands further refined the list. Tazarotene-induced gene-1 (Tig1) and CCAAT/enhancer binding protein-alpha (C/ebpalpha) were chosen for further study. Expression of both genes was low in endometrial cancer cell lines and clinical samples but high in normal endometrial tissues. Bisulfite sequencing, restriction analysis, and/or methylation-specific PCR revealed aberrant methylation of the CpG island in the Tig1 gene of all 6 endometrial cancer cell lines examined and 4 of 18 clinical endometrial cancers, whereas the C/ebpalpha promoter remained unmethylated in endometrial cancers. Chromatin immunoprecipitation showed increased acetylated histone H3 bound to both Tig1 and C/ebpalpha genes after treatment with 5-aza-2'-deoxycytidine and/or suberoylanilide bishydroxamide. Forced expression of either TIG1 or C/EBPalpha led to significant growth reduction of Ishikawa cells. Our data suggest that C/ebpalpha and Tig1 function as tumor suppressor proteins in endometrial cancers and that their reexpression may be a therapeutic target.
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Neoplasias do Endométrio/genética , Epigênese Genética/genética , Regulação Neoplásica da Expressão Gênica/genética , Genes Supressores de Tumor , Idoso , Idoso de 80 Anos ou mais , Proteína alfa Estimuladora de Ligação a CCAAT/genética , Linhagem Celular Tumoral , Imunoprecipitação da Cromatina , Ilhas de CpG/genética , Feminino , Histonas/metabolismo , Humanos , Complexo Mediador , Metilação , Pessoa de Meia-Idade , Fatores de Transcrição/genéticaRESUMO
Maintaining high relative dose intensity (RDI) is associated with improved outcomes, especially in patients with aggressive B-cell non-Hodgkin lymphoma (NHL). To evaluate changes in practice, we examined RDI, chemotherapy treatment patterns, dose delays and reductions, neutropenia and related consequences, and supportive care in 500 patients with aggressive B-cell NHL treated between 2006-2009. We then compared the results to a previous study of patients treated between 1993-2001. Relative to the previous study, rituximab was a common addition to CHOP-21 (91% vs. 3%), more patients received an RDI ≥ 85% (68% vs. 52%), and fewer patients experienced dose reductions (21% vs. 35%), though incidences of dose delays were similar (26% vs. 23%). Incidences of febrile neutropenia (FN; 12% vs. 21%) and FN-related hospitalizations (10% vs. 16%) were lower. Finally, more patients received primary prophylaxis with colony-stimulating factors (75% vs. 12%). Together, these results illustrate evolving practice patterns for patients with aggressive B-cell NHL.
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PURPOSE: HDAC inhibitors (HDACIs) have been shown to inhibit cancer cell proliferation, stimulate apoptosis, and induce cell cycle arrest. Our purpose was to investigate the antiproliferative effects of the HDACIs [suberoyl anilide bishydroxamine, valproic acid (VPA), trichostatin A, and sodium butyrate] against six endometrial cancer cell lines. EXPERIMENTAL DESIGN: Endometrial cancer cells were treated with a variety of HDACIs, and the effect on cell growth, cell cycle, and apoptosis was measured. The ability of VPA to inhibit the growth of endometrial tumors growing in immunodeficient mice was also assessed. RESULTS: Clonogenic assays showed that all cancer cell lines were sensitive to the growth inhibitory effect of HDACIs. Cell cycle analysis indicated that treatment with HDACIs decreased the proportion of cells in S phase and increased the proportion of cells in the G(0)-G(1) and/or G(2)-M phases of the cell cycle. Terminal deoxynucleotidyl transferase-mediated nick end labeling assays showed that HDACIs induced apoptosis. This was concomitant with altered expression of genes related to malignant phenotype, including an increase in p21(Waf1), p27(Kip7), and E-cadherin and a decrease in Bcl-2 and cyclin-D1 and -D2. Chromatin immunoprecipitation analysis revealed a remarkable increase in levels of acetylated histones associated with the p21 promoter after suberoyl anilide bishydroxamine treatment. In nude mice experiments, VPA inhibited significantly human uterine tumor growth without toxic side effects. CONCLUSIONS: These results suggest that HDACIs are effective in inhibiting growth of endometrial cancer cells in vitro and in nude mice, without toxic side effects. The findings raise the possibility that HDACIs may prove particularly effective in treatment of endometrial cancers.
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Neoplasias do Endométrio/tratamento farmacológico , Inibidores Enzimáticos/farmacologia , Inibidores de Histona Desacetilases , Ágar/química , Animais , Antineoplásicos/farmacologia , Apoptose , Western Blotting , Caderinas/biossíntese , Proteínas de Ciclo Celular/biossíntese , Divisão Celular , Linhagem Celular Tumoral , Cromatina/metabolismo , Ciclina D1/biossíntese , Ciclina D2 , Inibidor de Quinase Dependente de Ciclina p21 , Inibidor de Quinase Dependente de Ciclina p27 , Ciclinas/biossíntese , Relação Dose-Resposta a Droga , Neoplasias do Endométrio/patologia , Feminino , Citometria de Fluxo , Histonas/metabolismo , Humanos , Ácidos Hidroxâmicos/farmacologia , Marcação In Situ das Extremidades Cortadas , Camundongos , Camundongos Nus , Testes de Precipitina , Proteínas Proto-Oncogênicas c-bcl-2/biossíntese , Fase S , Oxibato de Sódio/farmacologia , Fatores de Tempo , Proteínas Supressoras de Tumor/biossíntese , Ácido Valproico/farmacologia , VorinostatRESUMO
This study evaluated the correlation between the risk of febrile neutropenia (FN) estimated by physicians and the risk of severe neutropenia or FN predicted by a validated multivariate model in patients with nonmyeloid malignancies receiving chemotherapy. Before patient enrollment, physician and site characteristics were recorded, and physicians self-reported the FN risk at which they would typically consider granulocyte colony-stimulating factor (G-CSF) primary prophylaxis (FN risk intervention threshold). For each patient, physicians electronically recorded their estimated FN risk, orders for G-CSF primary prophylaxis (yes/no), and patient characteristics for model predictions. Correlations between physician-assessed FN risk and model-predicted risk (primary endpoints) and between physician-assessed FN risk and G-CSF orders were calculated. Overall, 124 community-based oncologists registered; 944 patients initiating chemotherapy with intermediate FN risk enrolled. Median physician-assessed FN risk over all chemotherapy cycles was 20.0%, and median model-predicted risk was 17.9%; the correlation was 0.249 (95% CI, 0.179-0.316). The correlation between physician-assessed FN risk and subsequent orders for G-CSF primary prophylaxis (n = 634) was 0.313 (95% CI, 0.135-0.472). Among patients with a physician-assessed FN risk ≥ 20%, 14% did not receive G-CSF orders. G-CSF was not ordered for 16% of patients at or above their physician's self-reported FN risk intervention threshold (median, 20.0%) and was ordered for 21% below the threshold. Physician-assessed FN risk and model-predicted risk correlated weakly; however, there was moderate correlation between physician-assessed FN risk and orders for G-CSF primary prophylaxis. Further research and education on FN risk factors and appropriate G-CSF use are needed.
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Neutropenia Febril/epidemiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Comorbidade , Neutropenia Febril/tratamento farmacológico , Neutropenia Febril/etiologia , Feminino , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Humanos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Neoplasias/complicações , Neoplasias/diagnóstico , Neoplasias/tratamento farmacológico , Médicos , Risco , Estados Unidos , Adulto JovemRESUMO
Biosimilars of biologics used for cancer treatment and supportive care are expected to enter the U.S. market soon. Biosimilars will be highly similar to their reference products, but unlike generic drugs, not identical. Differences between a biosimilar and its reference product may arise because of the complexity of biologics, and differences in the cell lines and processes used during manufacturing. Biosimilars will be approved in the United States through a regulatory pathway based on comparative analytical and clinical studies for their characterization and demonstration of no clinically meaningful differences from their reference products. Unlike generics, initial approval may not include interchangeability, as additional evidence may be required before a biosimilar could be approved as interchangeable with its reference product; interchangeable designation could allow pharmacy-level substitution without prescriber intervention. In some cases, the U.S. Food and Drug Administration (FDA) may extrapolate an indication that has not been formally investigated for the biosimilar but that is approved for the reference product. Robust safety monitoring of all biologics is important to track and accurately attribute adverse events, particularly because their inherent complexity and manufacturing differences make them susceptible to structural changes that can affect safety (e.g., immunogenicity). Accuracy of postapproval safety reports will partly depend on the biosimilar naming approach. Potential cost savings should be evaluated in the context of differences in manufacturers' patient-assistance programs, copayments, and institutional costs. A manufacturer's ability to ensure reliable supply of high-quality biosimilars should also be considered. Broad understanding of these issues is critical for oncologists preparing for their use in clinical practice.
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Antineoplásicos/uso terapêutico , Medicamentos Biossimilares/uso terapêutico , Neoplasias/tratamento farmacológico , Antineoplásicos/economia , Antineoplásicos/provisão & distribuição , Medicamentos Biossimilares/economia , Medicamentos Biossimilares/provisão & distribuição , Ensaios Clínicos como Assunto , Aprovação de Drogas , Substituição de Medicamentos , Europa (Continente) , Humanos , Guias de Prática Clínica como Assunto , Estados UnidosRESUMO
BACKGROUND: Human epidermal growth factor receptor 2 (HER2) is overexpressed in 25-30% of ovarian carcinoma cases and a correlation between increased HER2 expression and decreased survival has been demonstrated. HER2 is a ligand-less member of the HER family that functions as the preferred coreceptor for epidermal growth factor receptor (EGFR), HER3, and HER4. METHODS: An approach was developed to target HER2's role as a coreceptor using a monoclonal antibody, 2C4, which sterically hinders HER2's recruitment into a functional HER complex. RESULTS: HER2 was robustly expressed in all eight ovarian carcinoma cell lines; expression of EGFR and HER3 was variable. Even though four of the eight cell lines responded to EGF, 2C4 antibody moderately inhibited in vitro proliferation of only two cell lines (OVCA433 and SK-OV-3). Furthermore, ligand-stimulated p-MAPK expression was inhibited by 2C4 only in these two cell lines after exposure to EGF. Immunoprecipitation and eTag analysis revealed that OVCA433 expressed heterodimers of EGFR/HER2, and these heterodimers were disrupted after treatment with 2C4, whereas OVCA432 cells did not have these heterodimers. In murine xenograft experiments, the in vivo growth of OVCA433, but not of OVCA432, ovarian carcinoma cells was significantly inhibited by 2C4 treatment of the mice. CONCLUSION: 2C4 is able to disrupt the HER signaling pathway and inhibit the in vitro and in vivo growth of ovarian carcinoma cell lines. The response appears limited to lines in which HER2 heterodimers were able to transduce proliferative signals. Our findings suggest a strong rationale to conduct clinical trials of 2C4 in a subset of patients with ovarian tumors.