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1.
Br J Cancer ; 125(4): 495-509, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33911195

RESUMO

Obesity is a risk factor for at least 13 different types of cancer, many of which are hormonally driven, and is associated with increased cancer incidence and morbidity. Adult obesity rates are steadily increasing and a subsequent increase in cancer burden is anticipated. Obesity-related dysfunction can contribute to cancer pathogenesis and treatment resistance through various mechanisms, including those mediated by insulin, leptin, adipokine, and aromatase signalling pathways, particularly in women. Furthermore, adiposity-related changes can influence tumour vascularity and inflammation in the tumour microenvironment, which can support tumour development and growth. Trials investigating non-pharmacological approaches to target the mechanisms driving obesity-mediated cancer pathogenesis are emerging and are necessary to better appreciate the interplay between malignancy, adiposity, diet and exercise. Diet, exercise and bariatric surgery are potential strategies to reverse the cancer-promoting effects of obesity; trials of these interventions should be conducted in a scientifically rigorous manner with dose escalation and appropriate selection of tumour phenotypes and have cancer-related clinical and mechanistic endpoints. We are only beginning to understand the mechanisms by which obesity effects cell signalling and systemic factors that contribute to oncogenesis. As the rates of obesity and cancer increase, we must promote the development of non-pharmacological lifestyle trials for the treatment and prevention of malignancy.


Assuntos
Neoplasias Hormônio-Dependentes/prevenção & controle , Obesidade/terapia , Cirurgia Bariátrica , Ensaios Clínicos como Assunto , Dietoterapia , Terapia por Exercício , Feminino , Humanos , Masculino , Neoplasias Hormônio-Dependentes/etiologia , Neoplasias Hormônio-Dependentes/imunologia , Obesidade/complicações , Obesidade/imunologia
2.
Breast Cancer Res Treat ; 183(1): 217-226, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32607639

RESUMO

PURPOSE: It has been hypothesized that selenium (Se) can prevent cancer, and that Se deficiency may be associated with an increased risk of breast cancer. However, findings from epidemiological studies have been inconsistent. The objective of this study was to assess the association between Se intake and risk of breast cancer in the Women's Health Initiative (WHI). METHODS: This study included 145,033 postmenopausal women 50-79 years who completed baseline questionnaires between October 1993 and December 1998, which addressed dietary and supplemental Se intake and breast cancer risk factors. The association between baseline Se intake and incident breast cancer was examined in Cox proportional hazards analysis. RESULTS: During a mean follow-up of 15.5 years, 9487 cases of invasive breast cancer were identified. Total Se (highest versus lowest quartile: HR 1.00, 95% CI 0.92-1.09, Ptrend = 0.66), dietary Se (highest versus lowest quartile: HR 0.99, 95% CI 0.89-1.08, Ptrend = 0.61), and supplemental Se (yes versus no: HR 0.99, 95% CI 0.95-1.03) were not associated with breast cancer incidence. CONCLUSIONS: This study indicates that Se intake is not associated with incident breast cancer among postmenopausal women in the United States. Further studies are needed to confirm our findings by using biomarkers such as toenail Se to reduce the potential for misclassification of Se status.


Assuntos
Neoplasias da Mama/epidemiologia , Estrogênios , Inquéritos Epidemiológicos/estatística & dados numéricos , Neoplasias Hormônio-Dependentes/epidemiologia , Progesterona , Selênio , Saúde da Mulher , Idoso , Neoplasias da Mama/química , Neoplasias da Mama/prevenção & controle , Dieta , Suplementos Nutricionais , Feminino , Seguimentos , Humanos , Incidência , Pessoa de Meia-Idade , Proteínas de Neoplasias/análise , Neoplasias Hormônio-Dependentes/química , Neoplasias Hormônio-Dependentes/prevenção & controle , Pós-Menopausa , Modelos de Riscos Proporcionais , Receptores de Estrogênio/análise , Receptores de Progesterona/análise , Fatores de Risco , Inquéritos e Questionários
3.
Med Hypotheses ; 131: 109303, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31443747

RESUMO

The problems of immunoprotection from the environmental chemical carcinogens are discussed. The main experimental argument pro active immunization against carcinogens is a possibility of specific mucosal antibodies (Abs) to inhibit the penetration of carcinogens from environment and to stimulate its excretion with the following decreasing of carcinogen-DNA adducts levels. Hypothesis of cancer immunostimulation after active immunization against carcinogens is based on a high cancer risk in persons with high levels of serum Abs specific to environmental carcinogens coupled with high levels of Abs to endogenous steroids stimulating the proliferation of target cells, for example, Abs to benzo[a]pyrene together with Abs to estradiol. The active immunization could increase the cancer risk much more in those persons. The passive immunization could be an alternative safe approach to avoid this problem.


Assuntos
Carcinógenos Ambientais/toxicidade , Neoplasias/prevenção & controle , Vacinação , Animais , Anticorpos/sangue , Especificidade de Anticorpos , Autoanticorpos/imunologia , Carcinógenos/toxicidade , Carcinógenos Ambientais/farmacocinética , Linhagem Celular Tumoral , Cocarcinogênese , Adutos de DNA/imunologia , Feminino , Haptenos/imunologia , Humanos , Imunização Passiva , Masculino , Camundongos , Camundongos Endogâmicos , Neoplasias Experimentais/induzido quimicamente , Neoplasias Experimentais/imunologia , Neoplasias Experimentais/prevenção & controle , Neoplasias Hormônio-Dependentes/induzido quimicamente , Neoplasias Hormônio-Dependentes/imunologia , Neoplasias Hormônio-Dependentes/prevenção & controle , Ratos , Ratos Endogâmicos , Risco , Esteroides/imunologia , Vacinação/efeitos adversos
4.
Br J Surg ; 105(12): 1650-1657, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30003539

RESUMO

BACKGROUND: Obesity increases the risk of several types of cancer. Whether bariatric surgery influences the risk of obesity-related cancer is not clear. This study aimed to uncover the risk of hormone-related (breast, endometrial and prostate), colorectal and oesophageal cancers following obesity surgery. METHODS: This national population-based cohort study used data from the Hospital Episode Statistics database in England collected between 1997 and 2012. Propensity matching on sex, age, co-morbidity and duration of follow-up was used to compare cancer risk among obese individuals undergoing bariatric surgery (gastric bypass, gastric banding or sleeve gastrectomy) and obese individuals not undergoing such surgery. Conditional logistic regression provided odds ratios (ORs) with 95 per cent confidence intervals. RESULTS: In the study period, from a cohort of 716 960 patients diagnosed with obesity, 8794 patients who underwent bariatric surgery were matched exactly with 8794 obese patients who did not have surgery. Compared with the no-surgery group, patients who had bariatric surgery exhibited a decreased risk of hormone-related cancers (OR 0·23, 95 per cent c.i. 0·18 to 0·30). This decrease was consistent for breast (OR 0·25, 0·19 to 0·33), endometrium (OR 0·21, 0·13 to 0·35) and prostate (OR 0·37, 0·17 to 0·76) cancer. Gastric bypass resulted in the largest risk reduction for hormone-related cancers (OR 0·16, 0·11 to 0·24). Gastric bypass, but not gastric banding or sleeve gastrectomy, was associated with an increased risk of colorectal cancer (OR 2·63, 1·17 to 5·95). Longer follow-up after bariatric surgery strengthened these diverging associations. CONCLUSION: Bariatric surgery is associated with decreased risk of hormone-related cancers, whereas gastric bypass might increase the risk of colorectal cancer.


Assuntos
Cirurgia Bariátrica/estatística & dados numéricos , Neoplasias/etiologia , Obesidade/cirurgia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Cirurgia Bariátrica/mortalidade , Neoplasias da Mama/etiologia , Neoplasias da Mama/mortalidade , Neoplasias da Mama/prevenção & controle , Neoplasias Colorretais/etiologia , Neoplasias Colorretais/mortalidade , Neoplasias Colorretais/prevenção & controle , Neoplasias do Endométrio/etiologia , Neoplasias do Endométrio/mortalidade , Neoplasias do Endométrio/prevenção & controle , Neoplasias Esofágicas/etiologia , Neoplasias Esofágicas/mortalidade , Neoplasias Esofágicas/prevenção & controle , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Neoplasias/mortalidade , Neoplasias/prevenção & controle , Neoplasias Hormônio-Dependentes/etiologia , Neoplasias Hormônio-Dependentes/mortalidade , Neoplasias Hormônio-Dependentes/prevenção & controle , Obesidade/complicações , Obesidade/mortalidade , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/mortalidade , Complicações Pós-Operatórias/prevenção & controle , Pontuação de Propensão , Neoplasias da Próstata/etiologia , Neoplasias da Próstata/mortalidade , Neoplasias da Próstata/prevenção & controle , Fatores de Risco , Adulto Jovem
6.
Curr Opin Obstet Gynecol ; 27(1): 92-7, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25517358

RESUMO

PURPOSE OF REVIEW: Breast cancer is the most common cancer in women worldwide. This review will focus on current prevention strategies for women at high risk. RECENT FINDINGS: The identification of women who are at high risk of developing breast cancer is key to breast cancer prevention. Recent findings have shown that the inclusion of breast density and a panel of low-penetrance genetic polymorphisms can improve risk estimation compared with previous models. Preventive therapy with aromatase inhibitors has produced large reductions in breast cancer incidence in postmenopausal women. Tamoxifen confers long-term protection and is the only proven preventive treatment for premenopausal women. Several other agents, including metformin, bisphosphonates, aspirin and statins, have been found to be effective in nonrandomized settings. SUMMARY: There are many options for the prevention of oestrogen-positive breast cancer, in postmenopausal women who can be given a selective oestrogen receptor modulator or an aromatase inhibitor. It still remains unclear how to prevent oestrogen-negative breast cancer, which occurs more often in premenopausal women. Identification of women at high risk of the disease is crucial, and the inclusion of breast density and a panel of genetic polymorphisms, which individually have low penetrance, can improve risk assessment.


Assuntos
Inibidores da Aromatase/uso terapêutico , Neoplasias da Mama/prevenção & controle , Recidiva Local de Neoplasia/prevenção & controle , Neoplasias Hormônio-Dependentes/prevenção & controle , Moduladores Seletivos de Receptor Estrogênico/uso terapêutico , Tamoxifeno/uso terapêutico , Idade de Início , Aspirina , Biomarcadores Tumorais , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/mortalidade , Difosfonatos , Feminino , Humanos , Metformina , Neoplasias Hormônio-Dependentes/tratamento farmacológico , Neoplasias Hormônio-Dependentes/mortalidade , Resultado do Tratamento
7.
Proc Natl Acad Sci U S A ; 111(46): 16514-9, 2014 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-25368192

RESUMO

It recently has been recognized that men develop colonic adenomas and carcinomas at an earlier age and at a higher rate than women. In the Apc(Pirc/+) (Pirc) rat model of early colonic cancer, this sex susceptibility was recapitulated, with male Pirc rats developing twice as many adenomas as females. Analysis of large datasets revealed that the Apc(Min/+) mouse also shows enhanced male susceptibility to adenomagenesis, but only in the colon. In addition, WT mice treated with injections of the carcinogen azoxymethane (AOM) showed increased numbers of colonic adenomas in males. The mechanism underlying these observations was investigated by manipulation of hormonal status. The preponderance of colonic adenomas in the Pirc rat model allowed a statistically significant investigation in vivo of the mechanism of sex hormone action on the development of colonic adenomas. Females depleted of endogenous hormones by ovariectomy did not exhibit a change in prevalence of adenomas, nor was any effect observed with replacement of one or a combination of female hormones. In contrast, depletion of male hormones by orchidectomy (castration) markedly protected the Pirc rat from adenoma development, whereas supplementation with testosterone reversed that effect. These observations were recapitulated in the AOM mouse model. Androgen receptor was undetectable in the colon or adenomas, making it likely that testosterone acts indirectly on the tumor lineage. Our findings suggest that indirect tumor-promoting effects of testosterone likely explain the disparity between the sexes in the development of colonic adenomas.


Assuntos
Adenoma/epidemiologia , Carcinógenos/toxicidade , Neoplasias do Colo/epidemiologia , Di-Hidrotestosterona/toxicidade , Hormônios Esteroides Gonadais/fisiologia , Neoplasias Hormônio-Dependentes/epidemiologia , Adenoma/induzido quimicamente , Adenoma/fisiopatologia , Adenoma/prevenção & controle , Polipose Adenomatosa do Colo/epidemiologia , Polipose Adenomatosa do Colo/genética , Polipose Adenomatosa do Colo/fisiopatologia , Animais , Animais Congênicos , Azoximetano/toxicidade , Neoplasias do Colo/induzido quimicamente , Neoplasias do Colo/fisiopatologia , Neoplasias do Colo/prevenção & controle , Modelos Animais de Doenças , Estradiol/administração & dosagem , Estradiol/farmacologia , Feminino , Genes APC , Terapia de Reposição Hormonal , Humanos , Masculino , Acetato de Medroxiprogesterona/administração & dosagem , Acetato de Medroxiprogesterona/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Mutação , Neoplasias Hormônio-Dependentes/fisiopatologia , Neoplasias Hormônio-Dependentes/prevenção & controle , Orquiectomia , Especificidade de Órgãos , Ovariectomia , Pós-Menopausa , RNA Mensageiro/análise , Distribuição Aleatória , Ratos , Ratos Endogâmicos F344 , Ratos Mutantes , Receptores Androgênicos/biossíntese , Receptores Androgênicos/genética , Distribuição por Sexo , Especificidade da Espécie
8.
Ginekol Pol ; 85(4): 278-82, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24834705

RESUMO

OBJECTIVES: Changes of kinase activity of non-genomic cellular signaling pathway may influence the effectiveness of pharmacotherapy in case of hormone-dependent tumors. Our study investigated a possible interaction at the molecular level between an aqueous herbal extract of Epilobium angustifolium as well as a lipid-sterolic fruit extract of Serenoa repens and synthetic drugs used in the treatment of hormone-dependent cancers. MATERIAL AND METHODS: E. angustifolium and Serenoa repens extracts were orally administered to testosterone-induced rats for 21 days. Changes of RafA/Mapk3/Mapk1 mRNA levels were analyzed by real-time quantitative PCR using target specific primers. RESULTS: The level of RafA mRNA slightly increased in rats receiving Epilobium angustifolium (p = 0.076) and Serenoa repens (p = 0.016) extracts. Administration of these extracts resulted in significantly elevated Mapk1 and Mapk3 transcripts in the investigated animals (p < 0.05 for each extract). The levels of Mapk1 and Mapk3 mRNA strongly increased (p < 0.05 for each extract) in animals receiving concomitantly testosterone and the extracts, while RafA transcription slightly decreased (p < 0.05), as compared to controls. CONCLUSIONS: The results of our study may indicate a potential effect of S. repens and E. angustifolium extracts on the functioning of non-genomic cellular signaling kinases pathway. We investigated safety of these extracts to detect possible drug interactions between synthetic drugs used in the treatment of proliferative changes in hormone-dependent reproductive organs and herbal preparations.


Assuntos
Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Quinases de Proteína Quinase Ativadas por Mitógeno/efeitos dos fármacos , Extratos Vegetais/farmacologia , Serenoa , Administração Oral , Animais , Feminino , Neoplasias Hormônio-Dependentes/prevenção & controle , Reação em Cadeia da Polimerase/métodos , Ratos , Ratos Wistar , Transdução de Sinais/efeitos dos fármacos
9.
Artigo em Inglês | MEDLINE | ID: mdl-24857058

RESUMO

Risk for breast cancer can be easily and rapidly assessed using validated, quantitative models. Multiple randomized studies show that the selective estrogen response modifiers (SERMs) tamoxifen and raloxifene can safely reduce the risk of invasive breast cancer in both pre- and postmenopausal women. Treatment resulted in a 38% reduction in breast cancer incidence, and 42 women would need to be treated to prevent one breast cancer event in the first 10 years of follow-up. Reduction was larger in the first 5 years of follow-up than in years 5 to 10, but no studies treated patients for longer than 5 years. Thromboembolic events were significantly increased with all SERMs, whereas vertebral fractures were reduced. Tamoxifen provides net benefit to all premenopausal women who are at increased risk, whereas raloxifene reduces risk nearly as much in postmenopausal women and offers increased safety. Both tamoxifen and raloxifene reduce the incidence of in situ cancers. Lasofoxifene reduced the risk of breast cancer by 79% in postmenopausal women with osteoporosis. The MAP3 trial showed a 65% reduction in the annual incidence of invasive breast cancer in postmenopausal women who were at moderately increased risk for breast cancer who took the aromatase inhibitor exemestane. The IBIS-II trial showed a 53% reduction in the risk of invasive breast cancer in postmenopausal women aged 40 to 70 who took the aromatase inhibitor anastrozole. Of the 50 million white women in the United States aged 35 to 79, 2.4 million would have a positive benefit/risk index for chemoprevention.


Assuntos
Anticarcinógenos/uso terapêutico , Inibidores da Aromatase/uso terapêutico , Neoplasias da Mama/prevenção & controle , Neoplasias Hormônio-Dependentes/prevenção & controle , Moduladores Seletivos de Receptor Estrogênico/uso terapêutico , Adulto , Fatores Etários , Idoso , Anticarcinógenos/efeitos adversos , Inibidores da Aromatase/efeitos adversos , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Medicina Baseada em Evidências , Feminino , Humanos , Pessoa de Meia-Idade , Neoplasias Hormônio-Dependentes/epidemiologia , Neoplasias Hormônio-Dependentes/metabolismo , Neoplasias Hormônio-Dependentes/patologia , Fatores de Proteção , Medição de Risco , Fatores de Risco , Moduladores Seletivos de Receptor Estrogênico/efeitos adversos , Fatores Sexuais , Fatores de Tempo , Resultado do Tratamento
10.
Anticancer Drugs ; 25(7): 745-50, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24346139

RESUMO

Combined hormonal contraceptives (CHCs) contain estrogen and progestin, which can stimulate estrogen-sensitive and/or progesterone-sensitive breast cancer growth. Until recently, ethinylestradiol had been almost the only estrogen used for decades, and its dose has been greatly reduced over time. The first generations of birth control pills contained approximately five times more estrogen and four times more progestin than the latest contraceptives. Newer CHCs also contain steroids that more closely mimic the physiological estradiol (E2) and progesterone effects. The newer CHC formulations are thus expected to have less influence on the breast, although it is very difficult to demonstrate any difference among the recent available preparations in human studies. Recently, nomegestrol acetate (NOMAC), a neutral, nonandrogenic, progesterone-like profile progestin, has become available in combination with the 'natural' estrogen, E2. According to the literature, NOMAC/E2 is expected to have either a lesser stimulating effect or a neutral effect on estrogen-sensitive breast cancers. We performed an analysis of the available studies and a bibliographical review. The endocrine and metabolic effects of NOMAC/E2 formulation might lead to a lesser breast tissue stimulation. The data reported, confirmed through clinical studies, should be considered when choosing a hormonal contraceptive, especially when breast stimulation is a concern.


Assuntos
Neoplasias da Mama/prevenção & controle , Anticoncepcionais Orais Hormonais/efeitos adversos , Estradiol/efeitos adversos , Megestrol/efeitos adversos , Norpregnadienos/efeitos adversos , Mama/efeitos dos fármacos , Mama/metabolismo , Mama/patologia , Neoplasias da Mama/induzido quimicamente , Neoplasias da Mama/metabolismo , Proliferação de Células/efeitos dos fármacos , Feminino , Humanos , Proteínas de Membrana/metabolismo , Neoplasias Hormônio-Dependentes/induzido quimicamente , Neoplasias Hormônio-Dependentes/metabolismo , Neoplasias Hormônio-Dependentes/prevenção & controle , Receptores de Progesterona/metabolismo , Risco
11.
Anticancer Agents Med Chem ; 13(8): 1178-87, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23919747

RESUMO

Epidemiological and migratory evidence suggests that dietary soy consumption can lower the risk for breast cancer. The role of soy isoflavones in cancer prevention and promotion is somewhat unclear. There are two views in terms of soy isoflavones and breast cancer. One line of evidence suggests that soy and its isoflavones have exhibited cancer-preventive properties including lengthening the menstrual cycle, altering estrogen metabolism away from cancerous compounds, and demonstrating anti-proliferative properties in vivo. On the contrary, isoflavones found in soy products are suggested to behave as weak estrogens and as such, much speculation surrounds the influence of soy and/or its isoflavones on hormone-receptor-positive cancers. The objective of this review is to present the latest knowledge regarding the role of soy and its isoflavones with the development and advancement of breast cancer, the safety of soy isoflavones for breast cancer survivors, and a comparison of the carcinogenic effects in animal models following soy isoflavone and estrogen administration. This review compares and contrasts literature in terms of the anti-cancer and cancer-promoting effects of soy isoflavones and estrogen in humans and animal models. In conclusion, current human and animal data provide evidence for several anticancer properties of soy and/or its isoflavones. Although the specific quantities and constituents responsible for the observed anti-cancer effects have not been elucidated, it appears that soy isoflavones do not function as an estrogen, but rather exhibit anti-estrogenic properties. However, their metabolism differs between humans and animals and therefore the outcomes of animal studies may not be applicable to humans. The majority of breast cancer cases are hormone-receptor-positive; therefore, soy isoflavones should be considered a potential anti-cancer therapeutic agent and warrant further investigation.


Assuntos
Neoplasias da Mama/prevenção & controle , Estrogênios/metabolismo , Glycine max/metabolismo , Isoflavonas/metabolismo , Animais , Povo Asiático , Neoplasias da Mama/etnologia , Neoplasias da Mama/metabolismo , Feminino , Humanos , Isoflavonas/farmacologia , Neoplasias Hormônio-Dependentes/metabolismo , Neoplasias Hormônio-Dependentes/prevenção & controle , Fitoestrógenos/metabolismo , Fitoestrógenos/farmacologia , Glycine max/química , População Branca
12.
Horm Cancer ; 4(4): 195-207, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23632998

RESUMO

Small, occult, undiagnosed breast cancers are found at autopsy in up to 15.6 % of women dying from unrelated causes with an average of 7 % from eight separate studies. The mammographic detection threshold of breast tumors ranges from 0.88 to 1.66 cm in diameter based on the patient's age. Tumor growth rates, expressed as "effective doubling times," vary from 10 to >700 days. We previously reported two models, based on iterative analysis of these parameters, to describe the biologic behavior of undiagnosed, occult breast tumors. Our models facilitate interpretation of the Women's Health Initiative (WHI) and antiestrogen breast cancer prevention studies. A nude mouse xenograft model was used to validate our assumption that breast tumors grow in a log-linear fashion. We then used our previously reported occult tumor growth (OTG) and computer-simulated tumor growth models to analyze various clinical trial data. Parameters used in the OTG model included a 200-day effective doubling time, 7 % prevalence of occult tumors, and 1.16 cm detection threshold. These models had been validated by comparing predicted with observed incidence of breast cancer in eight different populations of women. Our model suggests that menopausal hormone therapy with estrogens plus a progestogen (E + P) in the WHI trial primarily promoted the growth of pre-existing, occult lesions and minimally initiated de novo tumors. We provide a potential explanation for the lack of an increase in breast cancer incidence in the subgroup of women in the WHI who had not received E + P prior to randomization. This result may have reflected a leftward skew in the distribution of occult tumor doublings and insufficient time for stimulated tumors to reach the detection threshold. Our model predicted that estrogen alone reduced the incidence of breast cancer as a result of apoptosis. Understanding of the biology of occult tumors suggests that breast cancer "prevention" with antiestrogens or aromatase inhibitors represents early treatment rather than a reduction in de novo tumor formation. Our models suggest that occult, undiagnosed tumors are prevalent, grow slowly, and are the biologic targets of a hormone therapy in menopausal women and of antiestrogen therapy for prevention.


Assuntos
Antineoplásicos Hormonais/administração & dosagem , Neoplasias da Mama/patologia , Terapia de Reposição de Estrogênios , Modelos Biológicos , Tamoxifeno/administração & dosagem , Animais , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/prevenção & controle , Proliferação de Células , Simulação por Computador , Estrogênios/administração & dosagem , Feminino , Seguimentos , Humanos , Incidência , Camundongos , Camundongos Nus , Pessoa de Meia-Idade , Transplante de Neoplasias , Neoplasias Hormônio-Dependentes/epidemiologia , Neoplasias Hormônio-Dependentes/patologia , Neoplasias Hormônio-Dependentes/prevenção & controle , Ensaios Clínicos Controlados Aleatórios como Assunto , Risco , Resultado do Tratamento , Carga Tumoral
13.
Am J Clin Nutr ; 96(5): 1173S-8S, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23053550

RESUMO

Evidence from epidemiologic studies has suggested that carotenoids, and lycopene in particular, decrease the risk of cancer: however, not all studies support this view. To gain insight into the molecular mechanisms whereby lycopene and other carotenoids may exert their chemoprotective effects, we and others performed a series of studies that used a large panel of cancer cell lines of different lineages and animal models of human cancer. In this review we address some of the mechanisms proposed for the cancer-preventive activity of tomato lycopene, focusing on the induction of the antioxidant response element transcription system and the inhibition of the transcriptional activity of sex hormones, such as estrogens and androgens, and the activity of growth factors, such as insulin-like growth factor. We also considered the modulation by lycopene of the transcription factors peroxisome proliferator-activated receptor, retinoid X receptor, liver X receptor, and activating protein-1. The ligands and the phytonutrient regulators of these transcription systems contain electrophilic active groups, whereas lycopene and nonxanthophylic carotenoids are devoid of them. Thus, we suggest that at least some of the cellular effects of carotenoids are mediated through their derivatives formed either by chemical oxidation or by enzymatic cleavage inside the cells. This review highlights findings that pertain to this exciting avenue of research, which is currently under intense scrutiny in several laboratories worldwide.


Assuntos
Neoplasias da Mama/prevenção & controle , Carotenoides/farmacologia , Neoplasias do Endométrio/prevenção & controle , Fatores de Transcrição/fisiologia , Ativação Transcricional/efeitos dos fármacos , Animais , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Neoplasias do Endométrio/genética , Neoplasias do Endométrio/metabolismo , Feminino , Humanos , Licopeno , Masculino , Neoplasias Hormônio-Dependentes/genética , Neoplasias Hormônio-Dependentes/metabolismo , Neoplasias Hormônio-Dependentes/prevenção & controle , Transdução de Sinais/efeitos dos fármacos , Fatores de Transcrição/metabolismo
14.
Steroids ; 77(11): 1107-12, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22801352

RESUMO

Calcitriol (1,25-dihydroxyvitamin D(3)), the hormonally active form of vitamin D, inhibits the growth of many malignant cells including breast cancer (BCa) cells. The mechanisms of calcitriol anticancer actions include cell cycle arrest, stimulation of apoptosis and inhibition of invasion, metastasis and angiogenesis. In addition we have discovered new pathways of calcitriol action that are especially relevant in inhibiting the growth of estrogen receptor positive (ER+) BCa cells. Calcitriol suppresses COX-2 expression and increases that of 15-PGDH thereby reducing the levels of inflammatory prostaglandins (PGs). Our in vitro and in vivo studies show that calcitriol decreases the expression of aromatase, the enzyme that catalyzes estrogen synthesis selectively in BCa cells and in the mammary adipose tissue surrounding BCa, by a direct repression of aromatase transcription via promoter II as well as an indirect effect due to the reduction in the levels of PGs, which are major stimulator of aromatase transcription through promoter II. Calcitriol down-regulates the expression of ERα and thereby attenuates estrogen signaling in BCa cells including the proliferative stimulus provided by estrogens. Thus the inhibition of estrogen synthesis and signaling by calcitriol and its anti-inflammatory actions will play an important role in inhibiting ER+BCa. We hypothesize that dietary vitamin D would exhibit similar anticancer activity due to the presence of the enzyme 25-hydroxyvitamin D-1α-hydroxylase (CYP27B1) in breast cells ensuring conversion of circulating 25-hydroxyvitamin D to calcitriol locally within the breast micro-environment where it can act in a paracrine manner to inhibit BCa growth. Cell culture and in vivo data in mice strongly suggest that calcitriol and dietary vitamin D would play a beneficial role in the prevention and/or treatment of ER+BCa in women.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Neoplasias Hormônio-Dependentes/tratamento farmacológico , Receptores de Estrogênio/metabolismo , Vitamina D/farmacologia , Vitaminas/farmacologia , Antineoplásicos/administração & dosagem , Antineoplásicos/uso terapêutico , Inibidores da Aromatase/farmacologia , Inibidores da Aromatase/uso terapêutico , Neoplasias da Mama/metabolismo , Neoplasias da Mama/prevenção & controle , Calcitriol/farmacologia , Calcitriol/uso terapêutico , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Suplementos Nutricionais , Estrogênios/metabolismo , Feminino , Humanos , Neoplasias Hormônio-Dependentes/metabolismo , Neoplasias Hormônio-Dependentes/prevenção & controle , Vitamina D/administração & dosagem , Vitamina D/uso terapêutico , Vitaminas/administração & dosagem , Vitaminas/uso terapêutico
15.
Front Biosci (Landmark Ed) ; 17(6): 2035-58, 2012 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-22652763

RESUMO

Plant phytoalexins are a class of low molecular weight compounds that accumulate in response to biotic and abiotic elicitors such as pathogens, wounding, freezing, UV light, and exposure to agricultural chemicals. Phytoalexins have been identified in at least 75 plants including cruciferous vegetables, soybean, garlic, tomato, rice, beans, and potatoes suggesting plants may be a rich source of cancer-fighting compounds. Preclinical evidence suggests these compounds possess anticancer properties including an inhibition of microbial activity, cell proliferation, invasion and metastasis, hormonal stimulation, and stimulatory effects on expression of metabolizing enzymes. This review highlights the plausible molecular mechanisms through which phytoalexins regulate biological processes that can impinge cancer development. Targets of phytoalexins include signal transduction pathways, transcription factors, cell cycle checkpoints, intrinsic and extrinsic apoptotic pathways, cell invasion and matrix metalloproteinase, nuclear receptors, and the phase II detoxification pathway. Additional research should address physiological relevant dietary concentrations, combinations of phytoalexins and interactions with other dietary compounds, duration of exposure, and tissue specificity as variables that influence the effectiveness of phytoalexins on normal and cancerous processes.


Assuntos
Anticarcinógenos/farmacologia , Neoplasias/prevenção & controle , Sesquiterpenos/farmacologia , Animais , Anti-Infecciosos/farmacologia , Anticarcinógenos/farmacocinética , Apoptose/efeitos dos fármacos , Disponibilidade Biológica , Proliferação de Células/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Antagonistas de Hormônios/farmacologia , Humanos , Invasividade Neoplásica/prevenção & controle , Metástase Neoplásica/prevenção & controle , Neoplasias Hormônio-Dependentes/prevenção & controle , Sesquiterpenos/farmacocinética , Fitoalexinas
16.
Jpn J Clin Oncol ; 42(7): 569-77, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22593639

RESUMO

Men are at a higher risk of developing bladder cancer than women. Since bladder cancer cell lines and tissues were found to express the androgen receptor, efforts have been made to inspect whether androgen-mediated androgen receptor signals are implicated in bladder carcinogenesis as well as cancer progression. Mounting evidence supports the view that bladder cancer is a member of the endocrine-related tumors and may clearly explain the gender-specific difference in the incidence. However, the underlying mechanisms of how androgen receptor signals regulate bladder cancer growth are still far from fully characterized. Moreover, it remains controversial whether the androgen receptor pathway always plays a dominant role in bladder cancer progression. In this review, we summarize the available data on the involvement of androgen receptor signaling in bladder cancer. In particular, current evidence demonstrating the stimulatory effects of androgens on tumor progression or, more convincingly, tumorigenesis via the androgen receptor pathway may offer great potential for androgen deprivation as a therapeutic or chemopreventive option in patients with bladder cancer.


Assuntos
Neoplasias Hormônio-Dependentes/metabolismo , Receptores Androgênicos/metabolismo , Neoplasias da Bexiga Urinária/metabolismo , Animais , Butilidroxibutilnitrosamina , Carcinógenos , Castração , Modelos Animais de Doenças , Progressão da Doença , Medicina Baseada em Evidências , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Incidência , Masculino , Neoplasias Hormônio-Dependentes/induzido quimicamente , Neoplasias Hormônio-Dependentes/epidemiologia , Neoplasias Hormônio-Dependentes/prevenção & controle , Fatores de Risco , Fatores Sexuais , Transdução de Sinais , Neoplasias da Bexiga Urinária/induzido quimicamente , Neoplasias da Bexiga Urinária/epidemiologia , Neoplasias da Bexiga Urinária/prevenção & controle
17.
Cancer Epidemiol Biomarkers Prev ; 21(7): 1038-48, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22586072

RESUMO

BACKGROUND: Autopsy studies report a reservoir of small, occult, undiagnosed breast cancers in up to 15.6% of women dying from unrelated causes. The effective doubling times (EDT) of these occult neoplasms range from 70 to 350 days and mammographic detection threshold diameters from 0.88 to 1.66 cm. Modeling of the biologic behavior of these occult tumors facilitates interpretation of tamoxifen breast cancer prevention and menopausal hormone therapy studies. METHODS: We used iterative and mathematical techniques to develop a model of occult tumor growth (OTG) whose parameters included prevalence, EDT, and detection threshold. The model was validated by comparing predicted with observed incidence of breast cancer in several populations. RESULTS: Iterative analysis identified a 200-day EDT, 7% prevalence and 1.16 cm detection threshold as optimal parameters for an OTG model as judged by comparison with Surveillance Epidemiology and End Results (SEER) population incidence rates in the United States. We validated the model by comparing predicted incidence rates with those observed in five separate population databases, in three long-term contralateral breast cancer detection studies, and with data from a computer-simulated tumor growth (CSTG) model. Our model strongly suggests that breast cancer prevention with anti-estrogens or aromatase inhibitors represents early treatment not prevention. In addition, menopausal hormone therapy does not primarily induce de novo tumors but promotes the growth of occult lesions. CONCLUSIONS: Our OGTG model suggests that occult, undiagnosed tumors are prevalent, grow slowly, and are the biologic targets of anti-estrogen therapy for prevention and hormone therapy for menopausal women.


Assuntos
Neoplasias da Mama/patologia , Neoplasias da Mama/prevenção & controle , Terapia de Reposição Hormonal , Menopausa , Modelos Estatísticos , Neoplasias Hormônio-Dependentes/patologia , Neoplasias Hormônio-Dependentes/prevenção & controle , Idoso , Antineoplásicos Hormonais/administração & dosagem , Neoplasias da Mama/epidemiologia , Feminino , Humanos , Incidência , Pessoa de Meia-Idade , Neoplasias Hormônio-Dependentes/epidemiologia , Tamoxifeno/administração & dosagem , Estados Unidos/epidemiologia
18.
Breast Cancer Res Treat ; 134(2): 727-34, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22588672

RESUMO

Weight gain is commonly reported by breast cancer patients on tamoxifen or aromatase inhibitors. Since weight gain may impact on outcome and compliance we have prospectively assessed the effects of these agents on weight change in three randomised trials for the treatment or prevention of breast cancer. Data on weight change in postmenopausal women from three large clinical trials investigating endocrine therapy for the treatment or prevention of breast cancer were analysed (ATAC, IBIS-I and IBIS-II). In the IBIS-I study, mean weight change on tamoxifen was +0.1 kg (SD 0.1) compared with +0.3 kg (SD 0.1) in women taking the placebo (P = 0.3) between baseline and 12 months of follow-up. In the IBIS-II trial, no statistically significant difference was found between anastrozole and placebo after 12 months of follow-up [+0.8 kg (SD 5.3) vs. +0.5 kg (SD 7.4), P = 0.5]. In the ATAC trial, no statistically significant differences in weight gain between anastrozole and tamoxifen were found after 12 months of follow-up [+1.4 kg (SD 3.9) vs. +1.5 kg (SD 4.0), P = 0.4]. Significant baseline predictors for gaining more than 5 kg of weight after 12 months of follow-up were: being younger than 60 years old, smoking and mastectomy. All three trials demonstrate that weight gain occurs primarily within the first 12 months of active treatment in a subset of patients. In the prevention trials, weight gain does not differ between anastrozole, tamoxifen and placebo and also did not differ between anastrozole and tamoxifen in the treatment trial.


Assuntos
Antineoplásicos Hormonais/efeitos adversos , Neoplasias da Mama/prevenção & controle , Neoplasias Hormônio-Dependentes/prevenção & controle , Nitrilas/efeitos adversos , Tamoxifeno/efeitos adversos , Triazóis/efeitos adversos , Aumento de Peso/efeitos dos fármacos , Idoso , Anastrozol , Antineoplásicos Hormonais/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Quimioterapia Adjuvante , Método Duplo-Cego , Feminino , Humanos , Pessoa de Meia-Idade , Neoplasias Hormônio-Dependentes/tratamento farmacológico , Nitrilas/uso terapêutico , Pós-Menopausa , Ensaios Clínicos Controlados Aleatórios como Assunto , Estudos Retrospectivos , Fatores de Risco , Tamoxifeno/uso terapêutico , Triazóis/uso terapêutico
19.
Rev. senol. patol. mamar. (Ed. impr.) ; 25(1): 8-13, ene.-mar. 2012.
Artigo em Espanhol | IBECS | ID: ibc-105629

RESUMO

Introducción y objetivos: El cáncer de mama constituye un grupo heterogéneo de tumores. La positividad para receptores de estrógenos se ha considerado como un factor de buen pronóstico. Este concepto ha ido cambiando con el estudio de series mayores y seguimientos más largos. El objetivo de esta revisión ha sido evaluar el patrón de recidiva de estos tumores con tiempos de seguimiento más largos. Materiales y métodos: Se llevó a cabo un estudio de revisión de casos en el que se compararon las recidivas entre tumores hormonodependientes y hormonoindependientes. Se evaluaron los casos de recidiva, local y sistémica, diagnosticados entre 1996 y 2010, con un total de 88 casos. La distribución de los casos fue: a) 65 de tumores hormonodependientes; b) 20 de tumores hormonoindependientes, y c) 3 desconocidos. El 99% de los pacientes con tumores con receptores de estrógenos positivos realizó tratamiento endocrino adyuvante. Resultados: El patrón de recidiva de los tumores hormonoindependientes empezó con un pico a los 2 años, y después disminuyó de forma abrupta. Este patrón difirió de los hormonodependientes, con un pico de recidiva entre el tercer y el sexto año, y posteriormente disminuyó de forma gradual durante seguimientos más largos (15-20 años). La regresión logística con la variable dependiente "sin recidiva a los 5 años" mostró una asociación con el tamaño del tumor (p = 0,029) y la positividad para receptores de estrógeno (p = 0,05). No hubo relación para las restantes variables incluidas en el modelo (edad, menopausia, afectación ganglionar, clasificación TNM). Conclusión: Estos datos confirman un patrón de recidiva diferente en los 2 grupos estudiados. Los carcinomas hormonodependientes tuvieron un riesgo de recidiva más elevado, alrededor de los 4-6 años, y posteriormente una disminución gradual. Por el contrario, en sólo el 16,8% de los tumores hormonoindependientes hubo recidiva después de los primeros 5 años de seguimiento(AU)


Introduction and aims: Breast cancer is a heterogeneous group of tumours. The oestrogen receptor positivity was seen as a good prognostic factor for recurrence and survival. This concept has changed with studies with longer follow-up and larger series. It is believed that this effect of better prognosis in hormone-dependent tumours is lost after the first five years of monitoring. Materials and methods: A case review study comparing recurrence between hormone-dependent tumours and tumours with negative oestrogen receptors was undertaken. We evaluated the cases of recurrence, local and systemic, diagnosed between 1996 and 2010, totalling 88 cases. Sixty-five cases were oestrogen receptor positive, 20 cases oestrogen receptor negative, and 3 cases unknown. Almost all (99%) patients with oestrogen receptor positive tumours received adjuvant hormone therapy. Results: The pattern of recurrence in negative estrogen receptors tumors began with an initial peak at 2 years, then steadily decreasing. This pattern differed from the hormone-dependent tumours, with a peak incidence of recurrence between the third and sixth years, and then gradually decreasing over longer follow-ups (15 to 20 years). Logistic regression with the dependent variable "without recurrence at 5 years follow-up" showed an association between tumour size (p=.029) and hormone-dependency (p=.05). No relationship was found in the remaining variables of the model (age, menopausal status, lymph node involvement, TNM classification). Conclusion: These data confirm a different pattern of recurrence in both groups. Hormone-dependent carcinomas had a higher risk of recurrence at about 4 to 6 years and then gradually decreased. By contrast, only 16.8% of negative oestrogen receptors tumours had a recurrence after the first 5 years of follow-up(AU)


Assuntos
Humanos , Feminino , Adulto , Carcinoma/complicações , Carcinoma/diagnóstico , Neoplasias da Mama/complicações , Neoplasias da Mama/diagnóstico , Neoplasias Hormônio-Dependentes/epidemiologia , Neoplasias Hormônio-Dependentes/prevenção & controle , Recidiva Local de Neoplasia/complicações , Recidiva Local de Neoplasia/diagnóstico , Antineoplásicos Hormonais/uso terapêutico , Neoplasias Hormônio-Dependentes/fisiopatologia , Neoplasias Hormônio-Dependentes , Modelos Logísticos
20.
In Vivo ; 26(2): 207-11, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22351660

RESUMO

UNLABELLED: While cervical cancer incidence and mortality rates have declined in the United States, this cancer represents a worldwide threat. Human papilloma viral infection causes cervical neoplasia (CIN). 3,3'-Diindolylmethane (DIM) prevents or inhibits the progression from cervical dysplasia to cancer. The aim of this study is to determine the most effective dose of DIM given continuously in food, that significantly increases serum interferon gamma levels (IFN-γ) in the K14-HPV16 transgenic mouse model for cervical cancer. MATERIALS AND METHODS: Five doses of DIM in food were administered to the mouse model for 20 weeks. Serum Interferon gamma (IFN-γ) levels and estrogen metabolite levels were quantified. RESULTS: At 1000 ppm DIM, serum IFN-γ concentrations were significantly increased (p<0.0396). The estrogen metabolites were unchanged. IFN-γ concentrations in CIN free mice and the percentage of CIN free transgenic mice were well correlated (r=0.88). DISCUSSION: Significant increases in IFN-γ serum concentrations that correlate with the percentage of CIN free mice in each group indicate that 1000 ppm of DIM in food may be the most effective dose for future studies. These results may eventually lead to new and effective vaccination strategies in women already infected with the human papilloma virus.


Assuntos
Anticarcinógenos/uso terapêutico , Carcinoma de Células Escamosas/prevenção & controle , Papillomavirus Humano 16/genética , Indóis/uso terapêutico , Interferon gama/sangue , Queratina-14/genética , Neoplasias Hormônio-Dependentes/prevenção & controle , Proteínas Oncogênicas Virais/fisiologia , Proteínas E7 de Papillomavirus/fisiologia , Proteínas Repressoras/fisiologia , Displasia do Colo do Útero/prevenção & controle , Neoplasias do Colo do Útero/prevenção & controle , Administração Oral , Animais , Anticarcinógenos/administração & dosagem , Anticarcinógenos/farmacologia , Carcinoma de Células Escamosas/sangue , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patologia , Relação Dose-Resposta a Droga , Células Epiteliais/metabolismo , Estradiol/análogos & derivados , Estradiol/sangue , Estradiol/farmacocinética , Estradiol/toxicidade , Feminino , Indóis/administração & dosagem , Indóis/farmacologia , Camundongos , Camundongos Transgênicos , Neoplasias Hormônio-Dependentes/sangue , Neoplasias Hormônio-Dependentes/genética , Neoplasias Hormônio-Dependentes/patologia , Proteínas Oncogênicas Virais/biossíntese , Proteínas Oncogênicas Virais/genética , Proteínas E7 de Papillomavirus/biossíntese , Proteínas E7 de Papillomavirus/genética , Regiões Promotoras Genéticas , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/fisiologia , Proteínas Repressoras/biossíntese , Proteínas Repressoras/genética , Transgenes , Neoplasias do Colo do Útero/sangue , Neoplasias do Colo do Útero/genética , Neoplasias do Colo do Útero/patologia , Displasia do Colo do Útero/sangue , Displasia do Colo do Útero/genética , Displasia do Colo do Útero/patologia
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