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Malignant mammary tumor in female dogs: environmental contaminants.

Andrade FH, Figueiroa FC, Bersano PR, Bissacot DZ, Rocha NS - Diagn Pathol (2010)

Bottom Line: Five tumors were positive for estrogen receptors in immunohistochemical analysis.The contamination level was observed in more aggressive tumors.Results suggest the possible involvement of pyrethroid in the canine mammary tumor carcinogenesis.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Veterinary Medicine and Animal Science, São Paulo State University (UNESP) - Botucatu, SP, Brazil. rochanoeme@fmvz.unesp.br

ABSTRACT
Mammary tumors of female dogs have greatly increased in recent years, thus demanding rapid diagnosis and effective treatment in order to determine the animal survival. There is considerable scientific interest in the possible role of environmental contaminants in the etiology of mammary tumors, specifically in relation to synthetic chemical substances released into the environment to which living beings are either directly or indirectly exposed. In this study, the presence of pyrethroid insecticide was observed in adjacent adipose tissue of canine mammary tumor. High Precision Liquid Chromatography - HPLC was adapted to detect and identify environmental contaminants in adipose tissue adjacent to malignant mammary tumor in nine female dogs, without predilection for breed or age. After surgery, masses were carefully examined for malignant neoplastic lesions. Five grams of adipose tissue adjacent to the tumor were collected to detect of environmental contaminants. The identified pyrethroids were allethrin, cyhalothrin, cypermethrin, deltamethrin and tetramethrin, with a contamination level of 33.3%. Histopathology demonstrated six female dogs (66.7%) as having complex carcinoma and three (33.3%) with simple carcinoma. From these tumors, seven (77.8%) presented aggressiveness degree III and two (22.2%) degree I. Five tumors were positive for estrogen receptors in immunohistochemical analysis. The contamination level was observed in more aggressive tumors. This was the first report in which the level of environmental contaminants could be detected in adipose tissue of female dogs with malignant mammary tumor, by HPLC. Results suggest the possible involvement of pyrethroid in the canine mammary tumor carcinogenesis. Hence, the dog may be used as a sentinel animal for human breast cancer, since human beings share the same environment and basically have the same eating habits.

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Estrogen receptors' Immunohistochemical picture. Observe the nuclear pattern marking. Simple carcinoma, grade III, +++ for ER. 200X.
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Figure 5: Estrogen receptors' Immunohistochemical picture. Observe the nuclear pattern marking. Simple carcinoma, grade III, +++ for ER. 200X.

Mentions: It is said that in the hormonal carcinogenesis, unlike the one induced by virus or chemical agents, the cell proliferation does not need a specific triggering agent. Hormones induce the cell proliferation together with genetic mutations that will give rise to neoplasic cells [21]. However, Carreño et al. (1999) [22], shows that the hormone role in the carcinogenesis is restricted to the proliferation of cells that have already been changed by other carcinogens. Specific genes involved in the development of hormone-dependent neoplasias are still unknown. Nevertheless, it is believed that oncogenes, genes that are tumor suppressors and the genes of DNA repairment are involved in the hormonal carcinogenesis, especially in the one induced by sexual steroids [23]. Having said that, this study has shown that the detected contaminants were present in more aggressive tumors (degree III and +++ for estrogen receptors- Fig.5 and 6). Even though the literature showing that being positive for estrogen receptors may result in good prognostic for women [24], the results from this preliminary study suggest that the presence of pyrehroids in the peritumoral fat may have triggered the local estrogenic effect and thus triggered higher proliferation of tumor cells. Scheme below (Fig. 7) shows the carcinogenesis of mammary tumor and the role of pyrethroids in the proliferation of tumors.


Malignant mammary tumor in female dogs: environmental contaminants.

Andrade FH, Figueiroa FC, Bersano PR, Bissacot DZ, Rocha NS - Diagn Pathol (2010)

Estrogen receptors' Immunohistochemical picture. Observe the nuclear pattern marking. Simple carcinoma, grade III, +++ for ER. 200X.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2909155&req=5

Figure 5: Estrogen receptors' Immunohistochemical picture. Observe the nuclear pattern marking. Simple carcinoma, grade III, +++ for ER. 200X.
Mentions: It is said that in the hormonal carcinogenesis, unlike the one induced by virus or chemical agents, the cell proliferation does not need a specific triggering agent. Hormones induce the cell proliferation together with genetic mutations that will give rise to neoplasic cells [21]. However, Carreño et al. (1999) [22], shows that the hormone role in the carcinogenesis is restricted to the proliferation of cells that have already been changed by other carcinogens. Specific genes involved in the development of hormone-dependent neoplasias are still unknown. Nevertheless, it is believed that oncogenes, genes that are tumor suppressors and the genes of DNA repairment are involved in the hormonal carcinogenesis, especially in the one induced by sexual steroids [23]. Having said that, this study has shown that the detected contaminants were present in more aggressive tumors (degree III and +++ for estrogen receptors- Fig.5 and 6). Even though the literature showing that being positive for estrogen receptors may result in good prognostic for women [24], the results from this preliminary study suggest that the presence of pyrehroids in the peritumoral fat may have triggered the local estrogenic effect and thus triggered higher proliferation of tumor cells. Scheme below (Fig. 7) shows the carcinogenesis of mammary tumor and the role of pyrethroids in the proliferation of tumors.

Bottom Line: Five tumors were positive for estrogen receptors in immunohistochemical analysis.The contamination level was observed in more aggressive tumors.Results suggest the possible involvement of pyrethroid in the canine mammary tumor carcinogenesis.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Veterinary Medicine and Animal Science, São Paulo State University (UNESP) - Botucatu, SP, Brazil. rochanoeme@fmvz.unesp.br

ABSTRACT
Mammary tumors of female dogs have greatly increased in recent years, thus demanding rapid diagnosis and effective treatment in order to determine the animal survival. There is considerable scientific interest in the possible role of environmental contaminants in the etiology of mammary tumors, specifically in relation to synthetic chemical substances released into the environment to which living beings are either directly or indirectly exposed. In this study, the presence of pyrethroid insecticide was observed in adjacent adipose tissue of canine mammary tumor. High Precision Liquid Chromatography - HPLC was adapted to detect and identify environmental contaminants in adipose tissue adjacent to malignant mammary tumor in nine female dogs, without predilection for breed or age. After surgery, masses were carefully examined for malignant neoplastic lesions. Five grams of adipose tissue adjacent to the tumor were collected to detect of environmental contaminants. The identified pyrethroids were allethrin, cyhalothrin, cypermethrin, deltamethrin and tetramethrin, with a contamination level of 33.3%. Histopathology demonstrated six female dogs (66.7%) as having complex carcinoma and three (33.3%) with simple carcinoma. From these tumors, seven (77.8%) presented aggressiveness degree III and two (22.2%) degree I. Five tumors were positive for estrogen receptors in immunohistochemical analysis. The contamination level was observed in more aggressive tumors. This was the first report in which the level of environmental contaminants could be detected in adipose tissue of female dogs with malignant mammary tumor, by HPLC. Results suggest the possible involvement of pyrethroid in the canine mammary tumor carcinogenesis. Hence, the dog may be used as a sentinel animal for human breast cancer, since human beings share the same environment and basically have the same eating habits.

Show MeSH
Related in: MedlinePlus