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Updated: May 28, 2026
09:36
Changes in Mammary Gland Morphology and Breast Cancer Risk in Rats
Published on: October 16, 2010
Perinatal environmental exposures affect mammary development, function, and cancer risk in adulthood
Suzanne E Fenton1, Casey Reed, Retha R Newbold
1Division of the National Toxicology Program, National Institute of Environmental Health Sciences, National Institutes of Health, U.S. Department of Health and Human Services, Research Triangle Park, North Carolina 27709, USA. fentonse@niehs.nih.gov
Annual Review of Pharmacology and Toxicology
|October 25, 2011
Summary
Early thelarche, or breast development, is a growing health concern in girls. Environmental factors are suspected causes, necessitating further research into exposures and chemical impacts on mammary glands.
Area of Science:
- Endocrinology
- Environmental Health
- Reproductive Biology
Background:
- Puberty is a critical reproductive transition in mammals.
- Precocious puberty, particularly early thelarche (breast bud development), is a significant health issue in girls globally.
- The declining age of breast development is a concerning trend, with environmental factors implicated as a likely cause.
Purpose of the Study:
- To highlight the public health problem of precocious puberty and early thelarche in girls.
- To underscore the unknown causes behind the decreasing age of breast development.
- To identify critical research needs for understanding and potentially halting this trend.
Main Methods:
- Review of existing laboratory and epidemiological studies on environmental factors affecting breast development.
- Identification of knowledge gaps in current research.
- Formulation of recommendations for future research directions.
Main Results:
- Environmental factors are strongly suspected to play a major role in the decreasing age of breast development.
- Current research has identified some individual environmental factors but requires further advancement.
- Specific research needs include detailed recording of prenatal/neonatal exposures and chemical testing.
Conclusions:
- Further research is essential to understand the mechanisms behind early thelarche.
- Investigating prenatal and neonatal environmental exposures is crucial.
- Testing chemicals for mammary gland effects and understanding altered mechanisms are necessary to address the increasing trend of early puberty.
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