Abstract:Epidemiological and animal studies have indicated that 17beta-estradiol (E2) is involved in breast cancer; however, the mechanism is unclear. We found that E2 could be activated by epoxidation, resulting in its ability to inhibit nuclear DNA-dependent RNA synthesis, and to bind DNA, forming DNA adducts both in vitro and in vivo. Because epoxidation is required for the activation of many chemical carcinogens, including benzo(a)pyrene, 7,12-dimethylbenz(a)anthracene and aflatoxins, we proposed previously that E2… Show more
“…These reports are related indirectly to tumorigenesis, such as FSH producing adenoma (Tashiro et al 2000;Maruyama et al 2005;Roberts et al 2005). Other researchers have also reported a relationship between estrogen exposure and the risk of breast cancer (Yu 2002;Edlich et al 2005;Yager and Davidson 2006). Here, we present indirect evidence of hormone-induced tumorigenesis.…”
To determine whether the mammary gland can be used to secrete large quantities of a bioactive heterodimeric protein into milk, we used a bovine beta-casein promoter to target and express human follicle-stimulating hormone (hFSH) in the mammary gland into the milk of transgenic mice. We also identified the effects of hFSH leaked into the bloodstream. Transgenic mice produced a high level (up to 300 mIU/ml) of recombinant hFSH in the mammary gland. Human FSH was expressed in the mammary gland and brain, as determined by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry. In vitro bioactivity was also identified by cyclic AMP (cAMP) assay. The highest activity was showed in the transgenic mice line 11. However, hFSH leaked into the bloodstream was a powerful factor in the generation of breast and ovarian tumors from the transgenic mice line 11. These results suggest that change of endogenous hormones (FSH and progesterone) may affect the morphology and blood cell counts of peripheral blood and, especially, provoke breast and ovarian tumors.
“…These reports are related indirectly to tumorigenesis, such as FSH producing adenoma (Tashiro et al 2000;Maruyama et al 2005;Roberts et al 2005). Other researchers have also reported a relationship between estrogen exposure and the risk of breast cancer (Yu 2002;Edlich et al 2005;Yager and Davidson 2006). Here, we present indirect evidence of hormone-induced tumorigenesis.…”
To determine whether the mammary gland can be used to secrete large quantities of a bioactive heterodimeric protein into milk, we used a bovine beta-casein promoter to target and express human follicle-stimulating hormone (hFSH) in the mammary gland into the milk of transgenic mice. We also identified the effects of hFSH leaked into the bloodstream. Transgenic mice produced a high level (up to 300 mIU/ml) of recombinant hFSH in the mammary gland. Human FSH was expressed in the mammary gland and brain, as determined by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry. In vitro bioactivity was also identified by cyclic AMP (cAMP) assay. The highest activity was showed in the transgenic mice line 11. However, hFSH leaked into the bloodstream was a powerful factor in the generation of breast and ovarian tumors from the transgenic mice line 11. These results suggest that change of endogenous hormones (FSH and progesterone) may affect the morphology and blood cell counts of peripheral blood and, especially, provoke breast and ovarian tumors.
“…Epidemiological studies performed on animals indicated that 17 beta-estradiol (E2) was linked to breast cancer. It is known that E2 can be activated by epoxidation and that it is surely capable of inhibiting DNA synthesis for DNA- binding and adduct formation ( in vivo and in vitro) , playing an important role as a mammary carcinogenesis promoter [ 13 ].…”
Epidemiological studies enable us to analyze disease behavior, define risk factors and establish fundamental prognostic criteria, with the purpose of studying different types of diseases. The aim of this study was to determine the epidemiological characteristics of canine mammary tumors diagnosed during the period 2002-2012. The study was based on a retrospective study consisting of 1,917 biopsies of intact dogs that presented mammary gland lesions. Biopsies were sent to the Department of Pathology FMVZ-UNAM diagnostic service. The annual incidence of mammary tumors was 16.8%: 47.7% (benign) and 47.5% (malignant). The highest number of cases was epithelial, followed by mixed tumors. The most commonly diagnosed tumors were tubular adenoma, papillary adenoma, tubular carcinoma, papillary carcinoma, solid carcinoma, complex carcinoma and carcinosarcoma. Pure breeds accounted for 80% of submissions, and the Poodle, Cocker Spaniel and German Shepherd were consistently affected. Adult female dogs (9 to 12 years old) were most frequently involved, followed by 5- to 8-year-old females. Some association between breeds with histological types of malignant tumors was observed, but no association was found between breeds and BN. Mammary tumors in intact dogs had a high incidence. Benign and malignant tumors had similar frequencies, with an increase in malignant tumors in the past four years of the study. Epithelial tumors were more common, and the most affected were old adult females, purebreds and small-sized dogs. Mammary tumors in dogs are an important animal health problem that needs to be solved by improving veterinary oncology services in Mexico.
“…Esto significa que el efecto protector de la ovariohisterectomía disminuye rápidamente después de los primeros años de vida. Los estrógenos se pueden activar por epoxidación, lo que daña el dna e iniciará el proceso de carcinogénesis mamaria (Yu, 2002). Ninguna de las pacientes analizadas en esta investigación se castró antes de su primer celo, lo que permitió que su tejido mamario estuviera expuesto a una influencia hormonal significativa a lo largo de sus vidas.…”
Section: Discussionunclassified
“…Algunos factores de riesgo asociados con tumores de glándula mamaria son el género y la raza. Las hembras no castradas son las de mayor riesgo debido "al tropismo por la glándula mamaria que presentan los estrógenos naturales" (Yu, 2002). Asimismo, estudios epidemiológicos han descrito mayor susceptibilidad en razas de talla pequeña, entre ellas la Poodle, Maltés, Chihuahua, Cocker Spaniel, Springer Spaniel Inglés, Beagle, Yorkshire Terrier, Bichon Frisé, Springer Spaniel, Irish Setter y Pastor Alemán (Bronden et al, 2010).…”
Información y declaraciones adicionales en la página 11 Derechos de autor: Yaritza Salas et al. 2016 acceso abierto Distribuido bajo una Licencia Creative Commons Atribución 4.0 Internacional (CC-BY 4.0) Resumen Las características epidemiológicas y clínico-patológicas del tumor mamario canino es información valiosa para analizar el comportamiento de la enfermedad y son un recurso potencial para promover avances en el cáncer de mama en mujeres. El objetivo de este trabajo fue asociar las características histológicas del tumor mamario canino con factores potenciales de riesgo y el tiempo de sobrevida. De 80 perras enteras, se recolectaron 178 tumores mamarios. El análisis estadístico consistió en análisis de frecuencia de las variables de estudio, análisis bivariado con Chi cuadrado (χ 2), riesgo relativo, análisis de supervivencia Kaplan-Meier y un análisis de correspondencia múltiple que se utilizó para correlacionar el comportamiento biológico del tumor con la raza de las perras. La mayoría de las pacientes fueron mayores de 8 años de edad, con al menos un tumor maligno, casi siempre solitario, de gran tamaño y de mal pronóstico. Los tumores más frecuentes fueron el adenoma complejo, el tumor mixto benigno, el carcinoma complejo y el carcinoma tipo mixto. Las razas afectadas con mayor frecuencia fueron el Poodle, Cocker Spaniel y Dachshund; sólo el Cocker, el Labrador y el Pastor Alemán mostraron mayor riesgo. En general, los datos indican que el tumor mamario canino afecta sobre todo a hembras enteras, adultas mayores de 8 años de diversas razas; cursa con mortalidad alta y sobrevida corta en pacientes con tumor maligno de gran tamaño; sin embargo, las razas más afectadas no necesariamente son las más predispuestas. Este estudio no corrobora que exista un mayor riesgo de tumor mamario canino en perras nulíparas.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.