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1.
Bioelectromagnetics ; 45(4): 200-205, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38348555

RESUMO

A crucial aspect of IARC's evaluation of the relative carcinogenicity of agents is the communication of its conclusions. The present paper addressed the experimental risk perception literature pertaining to IARC's radiofrequency electromagnetic field evaluation communication, and derived specific recommendations for improving it.


Assuntos
Campos Eletromagnéticos , Neoplasias , Humanos , Campos Eletromagnéticos/efeitos adversos , Neoplasias/etiologia , Ondas de Rádio/efeitos adversos , Comunicação
2.
Regul Toxicol Pharmacol ; 150: 105646, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38777300

RESUMO

Environmental exposures are the main cause of cancer, and their carcinogenicity has not been fully evaluated, identifying potential carcinogens that have not been evaluated is critical for safety. This study is the first to propose a weight of evidence (WoE) approach based on computational methods to prioritize potential carcinogens. Computational methods such as read across, structural alert, (Quantitative) structure-activity relationship and chemical-disease association were evaluated and integrated. Four different WoE approach was evaluated, compared to the best single method, the WoE-1 approach gained 0.21 and 0.39 improvement in the area under the receiver operating characteristic curve (AUC) and Matthew's correlation coefficient (MCC) value, respectively. The evaluation of 681 environmental exposures beyond IARC list 1-2B prioritized 52 chemicals of high carcinogenic concern, of which 21 compounds were known carcinogens or suspected carcinogens, and eight compounds were identified as potential carcinogens for the first time. This study illustrated that the WoE approach can effectively complement different computational methods, and can be used to prioritize chemicals of carcinogenic concern.


Assuntos
Carcinógenos , Exposição Ambiental , Humanos , Carcinógenos/toxicidade , Exposição Ambiental/efeitos adversos , Relação Quantitativa Estrutura-Atividade , Medição de Risco , Animais
3.
Int J Cancer ; 152(5): 879-912, 2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-36134639

RESUMO

Knowledge of the role in cancer etiology of environmental exposures as pesticides is a prerequisite for primary prevention. We review 63 epidemiological studies on exposure to pesticides and cancer risk in humans published from 2017 to 2021, with emphasis on new findings, methodological approaches, and gaps in the existing literature. While much of the recent evidence suggests causal relationships between pesticide exposure and cancer, the strongest evidence exists for acute myeloid leukemia (AML) and colorectal cancer (CRC), diseases in which the observed associations were consistent across several studies, including high-quality prospective studies and those using biomarkers for exposure assessment, with some observing dose-response relationships. Though high-quality studies have been published since the IARC monograph on organophosphate insecticides in 2017, there are still gaps in the literature on carcinogenic evidence in humans for a large number of pesticides. To further knowledge, we suggest leveraging new techniques and methods to increase sensitivity and precision of exposure assessment, incorporate multi-omics data, and investigate more thoroughly exposure to chemical mixtures. There is also a strong need for better and larger population-based cohort studies that include younger and nonoccupationally exposed individuals, particularly during developmental periods of susceptibility. Though the existing evidence has limitations, as always in science, there is sufficient evidence to implement policies and regulatory action that limit pesticide exposure in humans and, hence, further prevent a significant burden of cancers.


Assuntos
Leucemia Mieloide Aguda , Exposição Ocupacional , Praguicidas , Humanos , Praguicidas/toxicidade , Estudos Prospectivos , Exposição Ambiental/efeitos adversos
4.
J Virol ; 96(14): e0206121, 2022 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-35770990

RESUMO

Several studies reported the presence of a recently discovered polyomavirus (PyV), Lyon IARC PyV (LIPyV), in human and domestic animal specimens. LIPyV has some structural similarities to well-established animal and human oncogenic PyVs, such as raccoon PyV and Merkel cell PyV (MCPyV), respectively. In this study, we demonstrate that LIPyV early proteins immortalize human foreskin keratinocytes. LIPyV LT binds pRb, accordingly cell cycle checkpoints are altered in primary human fibroblasts and keratinocytes expressing LIPyV early genes. Mutation of the pRb binding site in LT strongly affected the ability of LIPyV ER to induced HFK immortalization. LIPyV LT also binds p53 and alters p53 functions activated by cellular stresses. Finally, LIPyV early proteins activate telomerase reverse transcriptase (hTERT) gene expression, via accumulation of the Sp1 transcription factor. Sp1 recruitment to the hTERT promoter is controlled by its phosphorylation, which is mediated by ERK1 and CDK2. Together, these data highlight the transforming properties of LIPyV in in vitro experimental models, supporting its possible oncogenic nature. IMPORTANCE Lyon IARC PyV is a recently discovered polyomavirus that shows some structural similarities to well-established animal and human oncogenic PyVs, such as raccoon PyV and Merkel cell PyV, respectively. Here, we show the capability of LIPyV to efficiently promote cellular transformation of primary human cells, suggesting a possible oncogenic role of this virus in domestic animals and/or humans. Our study identified a novel virus-mediated mechanism of activation of telomerase reverse transcriptase gene expression, via accumulation of the Sp1 transcription factor. In addition, because the persistence of infection is a key event in virus-mediated carcinogenesis, it will be important to determine whether LIPyV can deregulate immune-related pathways, similarly to the well-established oncogenic viruses.


Assuntos
Infecções por Polyomavirus , Polyomavirus , Animais , Carcinogênese , Fibroblastos/virologia , Humanos , Queratinócitos/virologia , Poliomavírus das Células de Merkel/genética , Polyomavirus/genética , Polyomavirus/metabolismo , Infecções por Polyomavirus/virologia , Fator de Transcrição Sp1/metabolismo , Telomerase/genética , Proteína Supressora de Tumor p53/metabolismo
5.
Saudi Pharm J ; 31(2): 295-311, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36942272

RESUMO

Over the last two years, global regulatory authorities have raised safety concerns on nitrosamine contamination in several drug classes, including angiotensin II receptor antagonists, histamine-2 receptor antagonists, antimicrobial agents, and antidiabetic drugs. To avoid carcinogenic and mutagenic effects in patients relying on these medications, authorities have established specific guidelines in risk assessment scenarios and proposed control limits for nitrosamine impurities in pharmaceuticals. In this review, nitrosation pathways and possible root causes of nitrosamine formation in pharmaceuticals are discussed. The control limits of nitrosamine impurities in pharmaceuticals proposed by national regulatory authorities are presented. Additionally, a practical and science-based strategy for implementing the well-established control limits is notably reviewed in terms of an alternative approach for drug product N-nitrosamines without published AI information from animal carcinogenicity testing. Finally, a novel risk evaluation strategy for predicting and investigating the possible nitrosation of amine precursors and amine pharmaceuticals as powerful prevention of nitrosamine contamination is addressed.

6.
Int J Cancer ; 150(12): 1941-1947, 2022 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-35080783

RESUMO

Our study examines global patterns of Hodgkin lymphoma (HL) in 2020 and predicts the future incidence and mortality burden in 2040 using IARC's GLOBOCAN estimates of the number of new cases and deaths of HL in 185 countries. A total of 83 000 new cases of HL and 23 000 deaths from HL were estimated in 2020. In general, incidence and mortality rates were consistently higher in males (50% more cases and deaths than females) across world regions and countries. Incidence rates varied markedly by world region, at least 10-fold in both sexes, with the highest incidence rates observed in Southern Europe. Mortality exhibited an inverse pattern compared to incidence, with rates elevated in Western Asia and Northern Africa. The number of HL incident cases is predicted to rise to around 107 000 cases (a 30% increase) by 2040 due to demographic changes, assuming global rates in 2020 remains unchanged. The findings provide a baseline and impetus for developing strategies that aim to reduce the burden of HL in future decades.


Assuntos
Doença de Hodgkin , Europa (Continente)/epidemiologia , Feminino , Previsões , Saúde Global , Doença de Hodgkin/epidemiologia , Humanos , Incidência , Masculino , Mortalidade
7.
Int J Cancer ; 148(3): 560-571, 2021 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-32818326

RESUMO

Gaps in the translation of research findings to clinical management have been recognized for decades. They exist for the diagnosis as well as the management of cancer. The international standards for cancer diagnosis are contained within the World Health Organization (WHO) Classification of Tumours, published by the International Agency for Research on Cancer (IARC) and known worldwide as the WHO Blue Books. In addition to their relevance to individual patients, these volumes provide a valuable contribution to cancer research and surveillance, fulfilling an important role in scientific evidence synthesis and international standard setting. However, the multidimensional nature of cancer classification, the way in which the WHO Classification of Tumours is constructed, and the scientific information overload in the field pose important challenges for the translation of research findings to tumour classification and hence cancer diagnosis. To help address these challenges, we have established the International Collaboration for Cancer Classification and Research (IC3 R) to provide a forum for the coordination of efforts in evidence generation, standard setting and best practice recommendations in the field of tumour classification. The first IC3 R meeting, held in Lyon, France, in February 2019, gathered representatives of major institutions involved in tumour classification and related fields to identify and discuss translational challenges in data comparability, standard setting, quality management, evidence evaluation and copyright, as well as to develop a collaborative plan for addressing these challenges.


Assuntos
Detecção Precoce de Câncer/normas , Neoplasias/classificação , Neoplasias/diagnóstico , Medicina Baseada em Evidências , França , Humanos , Cooperação Internacional , Guias de Prática Clínica como Assunto , Organização Mundial da Saúde
8.
Regul Toxicol Pharmacol ; 113: 104639, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32147291

RESUMO

In 2019, the International Agency for Research on Cancer (IARC) "Preamble to the IARC Monographs" expanded guidance regarding the scientific approaches that should be employed in its monographs. These amendments to the monograph development process are an improvement but still fall short in several areas. While the revised Preamble lays out broad methods and approaches to evaluate scientific evidence, there is a lack of specificity with regard to how IARC Working Groups will conduct consistent evaluations in a standardized, objective, and transparent manner; document systematic review and evidence integration actions, and substantiate how these actions and decisions inform the ultimate classifications. Furthermore, no guidance is provided to ensure Working Groups consistently incorporate mechanistic evidence in a robust manner using a defined approach in the context of 21st century knowledge of modes of action. Nor are the conclusions of the working groups subjected to outside, independent scientific peer review. Continued improvements and modernization of the procedures for evaluating, presenting, and communicating study quality, and in the methods used to conduct and peer-review evidence-based decision making will benefit the Working Group members, the IARC Monographs Programme overall, and the international regulatory community and public who rely upon the monographs.


Assuntos
Neoplasias , Pesquisa , Carcinógenos , Tomada de Decisões , Humanos , Agências Internacionais , Neoplasias/induzido quimicamente , Saúde Pública
9.
Eur J Epidemiol ; 34(1): 1-4, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30547255

RESUMO

Circadian disruption (CD) was implicated in chains of cancer causation when the International Agency for Research on Cancer classified shift-work involving circadian disruption as probably carcinogenic in 2007. In the following decade, epidemiological studies into causal concepts associated with circadian disruption were inconclusive. Unappreciated complexity with an exclusive focus on shift-work, light-at-night, sleep, and melatonin in regard to circadian disruption may be accountable. With compelling non-epidemiological evidence, we posit that ubiquitous circadian disruption causes cancer and, moreover, that this is unexplored epidemiologically. This hypothesis offers a novel explanation why numerous studies in shift-workers evince inconsistent results: If circadian disruption is a ubiquitous causal phenomenon, confining assessments to the workplace, ignoring circadian disruption at play, and potential misclassification of 'who' is 'when' and 'how much' exposed to circadian disruption may disallow detecting the existence and magnitude of cancer risks. The rationale herein provides plausible explanations for previous observations and makes falsifiable predictions.


Assuntos
Transtornos Cronobiológicos/complicações , Neoplasias/etiologia , Jornada de Trabalho em Turnos/efeitos adversos , Causalidade , Humanos , Neoplasias/epidemiologia , Fatores de Risco , Tolerância ao Trabalho Programado
11.
Br J Nutr ; 120(10): 1171-1180, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30401003

RESUMO

This study aimed to estimate the number of new cancer cases attributable to diet among adults aged 30-84 years in France in 2015, where convincing or probable evidence of a causal association exists, and, in a secondary analysis, where at least limited but suggestive evidence of a causal association exists. Cancer cases attributable to diet were estimated assuming a 10-year latency period. Dietary intake data were obtained from the 2006 French National Nutrition and Health Survey. Counterfactual scenarios of dietary intake were based on dietary guidelines. Corresponding risk relation estimates were obtained from meta-analyses, cohort studies and one case-control study. Cancer incidence data were obtained from the French Network of Cancer Registries. Nationally, unfavourable dietary habits led to 16 930 new cancer cases, representing 5·4 % of all new cancer cases. Low intake of fruit and dietary fibre was the largest contributor to this burden, being responsible for 4787 and 4389 new cancer cases, respectively. If this is expanded to dietary component and cancer pairs with at least limited but suggestive evidence of a causal association, 36 049 new cancer cases, representing 11·6 % of all new cancer cases, were estimated to be attributable to diet. These findings suggest that unfavourable dietary habits lead to a substantial number of new cancer cases in France; however, there is a large degree of uncertainty as to the number of cancers attributable to diet, including through indirect mechanisms such as obesity, and therefore additional research is needed to determine how diet affects cancer risk.


Assuntos
Dieta , Neoplasias/epidemiologia , Neoplasias/etiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Estudos de Coortes , Fibras na Dieta , Feminino , França/epidemiologia , Frutas , Inquéritos Epidemiológicos , Humanos , Incidência , Masculino , Metanálise como Assunto , Pessoa de Meia-Idade , Inquéritos Nutricionais , Estado Nutricional , Obesidade/complicações , Sistema de Registros , Risco , Fatores de Risco
13.
Am J Ind Med ; 61(4): 277-281, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29397007

RESUMO

The International Agency for Research on Cancer (IARC) evaluates causes of cancer with help from independent international experts in an open and transparent manner. Countries, research and regulatory agencies, and other organizations adopt IARC evaluations for communication of human cancer hazards, and for strategies to prevent cancer. Scientists worldwide endorse IARC cancer evaluations and process. Those with economic interests, however, challenge IARC's cancer evaluations, most recently for glyphosate and red and processed meats, and are conducting a campaign including intervention from US Congressional Representatives to discredit IARC's review process and to undermine financial support-a campaign intimidating to IARC and Working Group members. Challenges to scientific interpretations serve to advance science and should be resolved by scientific experts who do not have conflicts of interest. Such interference does not bode well for the free flow of scientific information that informs and protects the public from risks of cancer.


Assuntos
Carcinógenos , Conflito de Interesses , Glicina/análogos & derivados , Herbicidas/efeitos adversos , Neoplasias/etiologia , Saúde Pública , Carne Vermelha/efeitos adversos , Glicina/efeitos adversos , Humanos , Agências Internacionais , Glifosato
14.
Clin Gastroenterol Hepatol ; 15(6): 892-900.e4, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27720911

RESUMO

BACKGROUND & AIMS: Population growth and changes in demographic structure are linked to trends in colorectal cancer (CRC) incidence. The aim of this study is to estimate future CRC incidence in the ageing population, and compare trends across developing and developed regions. METHODS: Cancer and population data were extracted from the International Agency for Research on Cancer. Annual incidence rates for the major types of cancer in 118 selected populations were extracted from 102 cancer registries in 39 countries worldwide. We selected 8 jurisdictions (from the United States, Europe, and Asia) that reported 20-year cancer incidence rates since 1988. Time series models were constructed to project cancer incidence, by sex and age, to 2030. Incidence rates for persons older than 65 years were combined and further adjusted for change of ageing population. We compared age-adjusted incidence rates among the jurisdictions. RESULTS: The total population older than 65 years old was 12,917,794 in 1988, and the number increased by almost 40% to 17,950,115 in 2007. In developed countries in the West CRC incidence is predicted to decrease by 16.3% in the United States, increase by 4.8% in the United Kingdom, and increase by 4.7% in Sweden by 2030. In developing countries, such as China (Shanghai), Croatia, and Costa Rica, CRC incidence is predicted to increase in a steep curve by 2030 because of the growing population and ageing effect; in 2030, the incidence increases were 60.5% for China, 47.0% for Croatia, and 18.5% for Costa Rica. We also predict CRC incidence will increase greatly by 2030 in Japan and Hong Kong, which are developed regions. CONCLUSIONS: With the exception of the United States, the incidence of CRC is expected to continue to rise in most regions in the coming decades, due to population growth and changes in demographic structure. The predicted increases are more marked in developing regions with limited health care resources.


Assuntos
Neoplasias Colorretais/epidemiologia , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Países Desenvolvidos , Países em Desenvolvimento , Feminino , Saúde Global , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Fatores Sexuais , Adulto Jovem
15.
Toxicol Appl Pharmacol ; 319: 39-46, 2017 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-28162991

RESUMO

BACKGROUND: The International Agency for Research on Cancer (IARC) recently developed a framework for evaluating mechanistic evidence that includes a list of 10 key characteristics of carcinogens. This framework is useful for identifying and organizing large bodies of literature on carcinogenic mechanisms, but it lacks sufficient guidance for conducting evaluations that fully integrate mechanistic evidence into hazard assessments. OBJECTIVES: We summarize the framework, and suggest approaches to strengthen the evaluation of mechanistic evidence using this framework. DISCUSSION: While the framework is useful for organizing mechanistic evidence, its lack of guidance for implementation limits its utility for understanding human carcinogenic potential. Specifically, it does not include explicit guidance for evaluating the biological significance of mechanistic endpoints, inter- and intra-individual variability, or study quality and relevance. It also does not explicitly address how mechanistic evidence should be integrated with other realms of evidence. Because mechanistic evidence is critical to understanding human cancer hazards, we recommend that IARC develop transparent and systematic guidelines for the use of this framework so that mechanistic evidence will be evaluated and integrated in a robust manner, and concurrently with other realms of evidence, to reach a final human cancer hazard conclusion. CONCLUSIONS: IARC does not currently provide a standardized approach to evaluating mechanistic evidence. Incorporating the recommendations discussed here will make IARC analyses of mechanistic evidence more transparent, and lead to assessments of cancer hazards that reflect the weight of the scientific evidence and allow for scientifically defensible decision-making.


Assuntos
Pesquisa Biomédica/normas , Carcinógenos/toxicidade , Agências Internacionais/normas , Neoplasias/induzido quimicamente , Pesquisa Biomédica/tendências , Tomada de Decisões , Humanos , Agências Internacionais/tendências , Neoplasias/diagnóstico , Neoplasias/epidemiologia
16.
Environ Health ; 16(1): 85, 2017 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-28793913

RESUMO

Hazard identification is a major scientific challenge, notably for environmental epidemiology, and is often surrounded, as the recent case of glyphosate shows, by debate arising in the first place by the inherently problematic nature of many components of the identification process. Particularly relevant in this respect are components less amenable to logical or mathematical formalization and essentially dependent on scientists' judgment. Four such potentially hazardous components that are capable of distorting the correct process of hazard identification are reviewed and discussed from an epidemiologist perspective: (1) lexical mix-up of hazard and risk (2) scientific questions as distinct from testable hypotheses, and implications for the hierarchy of strength of evidence obtainable from different types of study designs (3) assumptions in prior beliefs and model choices and (4) conflicts of interest. Four suggestions are put forward to strengthen a process that remains in several aspects judgmental, but not arbitrary, in nature.


Assuntos
Saúde Ambiental , Métodos Epidemiológicos , Substâncias Perigosas , Conflito de Interesses , Projetos de Pesquisa , Risco , Terminologia como Assunto
17.
Arch Toxicol ; 91(8): 2723-2743, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28374158

RESUMO

Glyphosate is the most widely used herbicide worldwide. It is a broad spectrum herbicide and its agricultural uses increased considerably after the development of glyphosate-resistant genetically modified (GM) varieties. Since glyphosate was introduced in 1974, all regulatory assessments have established that glyphosate has low hazard potential to mammals, however, the International Agency for Research on Cancer (IARC) concluded in March 2015 that it is probably carcinogenic. The IARC conclusion was not confirmed by the EU assessment or the recent joint WHO/FAO evaluation, both using additional evidence. Glyphosate is not the first topic of disagreement between IARC and regulatory evaluations, but has received greater attention. This review presents the scientific basis of the glyphosate health assessment conducted within the European Union (EU) renewal process, and explains the differences in the carcinogenicity assessment with IARC. Use of different data sets, particularly on long-term toxicity/carcinogenicity in rodents, could partially explain the divergent views; but methodological differences in the evaluation of the available evidence have been identified. The EU assessment did not identify a carcinogenicity hazard, revised the toxicological profile proposing new toxicological reference values, and conducted a risk assessment for some representatives uses. Two complementary exposure assessments, human-biomonitoring and food-residues-monitoring, suggests that actual exposure levels are below these reference values and do not represent a public concern.


Assuntos
Carcinógenos/toxicidade , Glicina/análogos & derivados , Herbicidas/toxicidade , Animais , Monitoramento Ambiental/métodos , União Europeia , Glicina/toxicidade , Humanos , Agências Internacionais , Valores de Referência , Medição de Risco/métodos , Roedores , Fatores de Tempo , Testes de Toxicidade/métodos , Glifosato
18.
Regul Toxicol Pharmacol ; 83: 66-80, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27871870

RESUMO

Perfluoroalkyls are stable synthetic chemicals, able to repel oils, fats and water. These compounds have been used in the manufacturing of products such as Teflon®, lubricants, paints, fire-fighting foams, coatings for pans, carpets, clothes, and paperboard for packaging, among others. It is believed that populations are exposed constantly to them. Its regulation in the world is under development and several controversies are in the course of litigation. One occupational study shows bladder cancer risk. This paper intends to review scientific information on the most critical perfluoroalkyl compound and proposes a procedure to get a cancer-risk categorization which PFOS can cause to populations. METHODS: As a guiding axis, we used the IARC process for developing monographs of carcinogenic risks. We used the SIGN guides for evaluating the quality of studies in human populations; and finally, we used the Squire method for evaluating studies in laboratory animals. Inadequate evidence of carcinogenicity was found in human studies mainly due to chance, threshold effect and confounders. In experimental animal studies, inadequate evidence of carcinogenicity was found in view of the number of affected species, different types of neoplasms, dose-response relationship and genotoxicity found in in-vivo and in-vitro studies. In this proposal, we concluded that cancer risk for PFOS, according to the IARC method, is not classifiable as carcinogenic to humans (group 3).


Assuntos
Ácidos Alcanossulfônicos/toxicidade , Carcinógenos/toxicidade , Transformação Celular Neoplásica/induzido quimicamente , Poluentes Ambientais/toxicidade , Fluorocarbonos/toxicidade , Neoplasias/induzido quimicamente , Doenças Profissionais/induzido quimicamente , Terminologia como Assunto , Ácidos Alcanossulfônicos/classificação , Animais , Testes de Carcinogenicidade , Carcinógenos/classificação , Transformação Celular Neoplásica/genética , Relação Dose-Resposta a Droga , Poluentes Ambientais/classificação , Fluorocarbonos/classificação , Humanos , Testes de Mutagenicidade , Neoplasias/epidemiologia , Neoplasias/genética , Doenças Profissionais/genética , Exposição Ocupacional/efeitos adversos , Saúde Ocupacional , Medição de Risco , Fatores de Risco
19.
Regul Toxicol Pharmacol ; 90: 185-196, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28866267

RESUMO

IARC has begun using ToxCast/Tox21 data in efforts to represent key characteristics of carcinogens to organize and weigh mechanistic evidence in cancer hazard determinations and this implicit inference approach also is being considered by USEPA. To determine how well ToxCast/Tox21 data can explicitly predict cancer hazard, this approach was evaluated with statistical analyses and machine learning prediction algorithms. Substances USEPA previously classified as having cancer hazard potential were designated as positives and substances not posing a carcinogenic hazard were designated as negatives. Then ToxCast/Tox21 data were analyzed both with and without adjusting for the cytotoxicity burst effect commonly observed in such assays. Using the same assignments as IARC of ToxCast/Tox21 assays to the seven key characteristics of carcinogens, the ability to predict cancer hazard for each key characteristic, alone or in combination, was found to be no better than chance. Hence, we have little scientific confidence in IARC's inference models derived from current ToxCast/Tox21 assays for key characteristics to predict cancer. This finding supports the need for a more rigorous mode-of-action pathway-based framework to organize, evaluate, and integrate mechanistic evidence with animal toxicity, epidemiological investigations, and knowledge of exposure and dosimetry to evaluate potential carcinogenic hazards and risks to humans.


Assuntos
Carcinógenos/toxicidade , Interpretação Estatística de Dados , Ensaios de Triagem em Larga Escala , Modelos Estatísticos , Neoplasias/classificação , Algoritmos , Animais , Testes de Carcinogenicidade , Humanos , Aprendizado de Máquina , Neoplasias/induzido quimicamente , Medição de Risco/métodos , Estados Unidos , United States Environmental Protection Agency
20.
Regul Toxicol Pharmacol ; 86: 157-166, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28274811

RESUMO

The International Agency for Research on Cancer (IARC) has formulated 10 key characteristics of human carcinogens to incorporate mechanistic data into cancer hazard classifications. The analysis used glyphosate as a case example to examine the robustness of IARC's determination of oxidative stress as "strong" evidence supporting a plausible cancer mechanism in humans. The IARC analysis primarily relied on 14 human/mammalian studies; 19 non-mammalian studies were uninformative of human cancer given the broad spectrum of test species and extensive use of formulations and aquatic testing. The mammalian studies had substantial experimental limitations for informing cancer mechanism including use of: single doses and time points; cytotoxic/toxic test doses; tissues not identified as potential cancer targets; glyphosate formulations or mixtures; technically limited oxidative stress biomarkers. The doses were many orders of magnitude higher than human exposures determined in human biomonitoring studies. The glyphosate case example reveals that the IARC evaluation fell substantially short of "strong" supporting evidence of oxidative stress as a plausible human cancer mechanism, and suggests that other IARC monographs relying on the 10 key characteristics approach should be similarly examined for a lack of robust data integration fundamental to reasonable mode of action evaluations.


Assuntos
Carcinógenos/classificação , Glicina/análogos & derivados , Agências Internacionais , Neoplasias/induzido quimicamente , Estresse Oxidativo , Animais , Carcinógenos/toxicidade , Glicina/administração & dosagem , Glicina/toxicidade , Humanos , Glifosato
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